flypig.co.uk

$ git diff
diff --git a/embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp
           b/embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp
index 34cff71f6e07..82cdf357f926 100644
--- a/embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp
+++ b/embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp
@@ -109,6 +109,7 @@ EmbedLiteCompositorBridgeParent::PrepareOffscreen()
 
   GLContext* context = static_cast<CompositorOGL*>(state->mLayerManager->GetCompositor())->gl();
   NS_ENSURE_TRUE(context, );
+  bool initSwapChain = false;
 
   // TODO: The switch from GLSCreenBuffer to SwapChain needs completing
   // See: https://phabricator.services.mozilla.com/D75055
@@ -125,6 +126,7 @@ EmbedLiteCompositorBridgeParent::PrepareOffscreen()
 
     SwapChain* swapChain = context->GetSwapChain();
     if (swapChain == nullptr) {
+      initSwapChain = true;
       swapChain = new SwapChain();
       new SwapChainPresenter(*swapChain);
       context->mSwapChain.reset(swapChain);
@@ -133,6 +135,13 @@ EmbedLiteCompositorBridgeParent::PrepareOffscreen()
     if (factory) {
       swapChain->Morph(std::move(factory));
     }
+
+    if (initSwapChain) {
+      bool success = context->ResizeScreenBuffer(mEGLSurfaceSize);
+      if (!success) {
+          NS_WARNING("Failed to create SwapChain back buffer");
+      }
+    }
   }
 }
 
$ git status
On branch sailfishos-esr91
Your branch is up-to-date with 'origin/sailfishos-esr91'.

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
  (commit or discard the untracked or modified content in submodules)
        modified:   embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp
        modified:   gecko-dev (untracked content)

no changes added to commit (use "git add" and/or "git commit -a")
$ git checkout embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp
Updated 1 path from the index

64:31.86 ${PROJECT}/gecko-dev/gfx/gl/GLScreenBuffer.h:98:60: error:
    ‘SurfaceCaps’ does not name a type; did you mean ‘SurfaceFactory’?
64:31.86    static UniquePtr<ReadBuffer> Create(GLContext* gl, const SurfaceCaps& caps,
64:31.86                                                             ^~~~~~~~~~~
64:31.86                                                             SurfaceFactory
64:31.88 ${PROJECT}/gecko-dev/gfx/gl/GLScreenBuffer.h:99:45:
    error: ‘GLFormats’ does not name a type; did you mean ‘eFormData’?
64:31.88                                        const GLFormats& formats,
64:31.88                                              ^~~~~~~~~
64:31.88                                              eFormData
[...]
64:32.20 ${PROJECT}/gecko-dev/gfx/gl/GLContext.h:3537:54:
    error: ‘SurfaceCaps’ does not name a type; did you mean ‘SurfaceFormat’?
64:32.20    bool InitOffscreen(const gfx::IntSize& size, const SurfaceCaps& caps);
64:32.20                                                       ^~~~~~~~~~~
64:32.20                                                       SurfaceFormat
64:32.23 ${PROJECT}/gecko-dev/gfx/gl/GLContext.h:3546:59:
    error: ‘SurfaceCaps’ does not name a type; did you mean ‘SurfaceFormat’?
64:32.24    bool CreateScreenBuffer(const gfx::IntSize& size, const SurfaceCaps& caps) {
64:32.24                                                            ^~~~~~~~~~~
64:32.24                                                            SurfaceFormat
[...]

1. Build code.
2. Examine compile-time errors.
3. Fix the first one or two erros shown.
4. Go to step 1.

$ sfdk engine exec
$ sb2 -t SailfishOS-devel-aarch64.default
$ source `pwd`/obj-build-mer-qt-xr/rpm-shared.env
$ make -j1 -C obj-build-mer-qt-xr/gfx/gl/

$ harbour-webview 
[D] unknown:0 - QML debugging is enabled. Only use this in a safe environment.
[D] main:30 - WebView Example
[D] main:44 - Using default start URL:  "https://www.flypig.co.uk/search/"
[D] main:47 - Opening webview
[D] unknown:0 - Using Wayland-EGL
library "libutils.so" not found
[...]
Created LOG for EmbedLiteLayerManager
=============== Preparing offscreen rendering context ===============
CONSOLE message:
OpenGL compositor Initialized Succesfully.
Version: OpenGL ES 3.2 V@0502.0 (GIT@704ecd9a2b, Ib3f3e69395, 1609240670)
    (Date:12/29/20)
Vendor: Qualcomm
Renderer: Adreno (TM) 619
FBO Texture Target: TEXTURE_2D
JSScript: ContextMenuHandler.js loaded
JSScript: SelectionPrototype.js loaded
JSScript: SelectionHandler.js loaded
JSScript: SelectAsyncHelper.js loaded
JSScript: FormAssistant.js loaded
JSScript: InputMethodHandler.js loaded
EmbedHelper init called
Available locales: en-US, fi, ru
Frame script: embedhelper.js loaded
Segmentation fault

$ gdb harbour-webview 
GNU gdb (GDB) Mer (8.2.1+git9)
[...]
(gdb) r
Starting program: /usr/bin/harbour-webview 
[...]
Thread 36 "Compositor" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 13568]
0x0000007ff110a378 in mozilla::gl::SwapChain::Size
    (this=this@entry=0x7ed81ce090)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
290     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:
    No such file or directory.
(gdb) bt
#0  0x0000007ff110a378 in mozilla::gl::SwapChain::Size
    (this=this@entry=0x7ed81ce090)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
#1  0x0000007ff3667cc8 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    PresentOffscreenSurface (this=0x7fc4b41c20)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:199
#2  0x0000007ff3680fe0 in mozilla::embedlite::nsWindow::PostRender
    (this=0x7fc4c331e0, aContext=<optimized out>)
    at mobile/sailfishos/embedshared/nsWindow.cpp:248
#3  0x0000007ff2a664fc in mozilla::widget::InProcessCompositorWidget::PostRender
    (this=0x7fc4658990, aContext=0x7f17ae4848)
    at widget/InProcessCompositorWidget.cpp:60
#4  0x0000007ff1291074 in mozilla::layers::LayerManagerComposite::Render
    (this=this@entry=0x7ed81afa80, aInvalidRegion=..., aOpaqueRegion=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/
    Compositor.h:575
#5  0x0000007ff12914f0 in mozilla::layers::LayerManagerComposite::
    UpdateAndRender (this=this@entry=0x7ed81afa80)
    at gfx/layers/composite/LayerManagerComposite.cpp:657
#6  0x0000007ff12918a0 in mozilla::layers::LayerManagerComposite::
    EndTransaction (this=this@entry=0x7ed81afa80, aTimeStamp=..., 
    aFlags=aFlags@entry=mozilla::layers::LayerManager::END_DEFAULT)
    at gfx/layers/composite/LayerManagerComposite.cpp:572
#7  0x0000007ff12d303c in mozilla::layers::CompositorBridgeParent::
    CompositeToTarget (this=0x7fc4b41c20, aId=..., aTarget=0x0,
    aRect=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/RefPtr.h:313
#8  0x0000007ff12b8784 in mozilla::layers::CompositorVsyncScheduler::Composite
    (this=0x7fc4d01e30, aVsyncEvent=...)
    at gfx/layers/ipc/CompositorVsyncScheduler.cpp:256
#9  0x0000007ff12b0bfc in mozilla::detail::RunnableMethodArguments
    <mozilla::VsyncEvent>::applyImpl<mozilla::layers::CompositorVsyncScheduler,
    void (mozilla::layers::CompositorVsyncScheduler::*)(mozilla::VsyncEvent
    const&), StoreCopyPassByConstLRef<mozilla::VsyncEvent>, 0ul> (args=...,
    m=<optimized out>, o=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:887
[...]
#21 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) p mFrontBuffer
$1 = std::shared_ptr<mozilla::gl::SharedSurface> (empty) = {get() = 0x0}
(gdb) 

  GLScreenBuffer* screen = context->Screen();
  MOZ_ASSERT(screen);

  if (screen->Size().IsEmpty() || !screen->PublishFrame(screen->Size())) {
    NS_ERROR("Failed to publish context frame");
  }

  // TODO: The switch from GLSCreenBuffer to SwapChain needs completing
  // See: https://phabricator.services.mozilla.com/D75055
  SwapChain* swapChain = context->GetSwapChain();
  MOZ_ASSERT(swapChain);

  const gfx::IntSize& size = swapChain->Size();
  if (size.IsEmpty() || !swapChain->PublishFrame(size)) {
    NS_ERROR("Failed to publish context frame");
  }

  UniquePtr<GLScreenBuffer> mScreen;
[...]
  GLScreenBuffer* Screen() const { return mScreen.get(); }

Delete all breakpoints? (y or n) y
(gdb) b CreateScreenBufferImpl
Breakpoint 7 at 0x7fb8e837d8: file gfx/gl/GLContext.cpp, line 2120.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 36 "Compositor" hit Breakpoint 7, mozilla::gl::GLContext::
    CreateScreenBufferImpl (this=this@entry=0x7eac109140, size=..., caps=...)
    at gfx/gl/GLContext.cpp:2120
2120                                           const SurfaceCaps& caps) {
(gdb) bt
#0  mozilla::gl::GLContext::CreateScreenBufferImpl
    (this=this@entry=0x7eac109140, size=..., caps=...)
    at gfx/gl/GLContext.cpp:2120
#1  0x0000007fb8e838ec in mozilla::gl::GLContext::CreateScreenBuffer
    (caps=..., size=..., this=0x7eac109140)
    at gfx/gl/GLContext.h:3517
#2  mozilla::gl::GLContext::InitOffscreen (this=0x7eac109140, size=...,
    caps=...)
    at gfx/gl/GLContext.cpp:2578
#3  0x0000007fb8e83ac8 in mozilla::gl::GLContextProviderEGL::CreateOffscreen
    (size=..., minCaps=..., flags=flags@entry=mozilla::gl::CreateContextFlags::
    REQUIRE_COMPAT_PROFILE, out_failureId=out_failureId@entry=0x7fa50ed378)
    at gfx/gl/GLContextProviderEGL.cpp:1443
#4  0x0000007fb8ee475c in mozilla::layers::CompositorOGL::CreateContext
    (this=0x7eac003420)
    at gfx/layers/opengl/CompositorOGL.cpp:250
#5  mozilla::layers::CompositorOGL::CreateContext (this=0x7eac003420)
    at gfx/layers/opengl/CompositorOGL.cpp:223
#6  0x0000007fb8f053bc in mozilla::layers::CompositorOGL::Initialize
    (this=0x7eac003420, out_failureReason=0x7fa50ed730)
    at gfx/layers/opengl/CompositorOGL.cpp:374
#7  0x0000007fb8fdcf7c in mozilla::layers::CompositorBridgeParent::NewCompositor
    (this=this@entry=0x7f8c99d3f0, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1534
#8  0x0000007fb8fe65e8 in mozilla::layers::CompositorBridgeParent::
    InitializeLayerManager (this=this@entry=0x7f8c99d3f0, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1491
#9  0x0000007fb8fe6730 in mozilla::layers::CompositorBridgeParent::
    AllocPLayerTransactionParent (this=this@entry=0x7f8c99d3f0,
    aBackendHints=..., aId=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1587
#10 0x0000007fbb2e31b4 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    AllocPLayerTransactionParent (this=0x7f8c99d3f0, aBackendHints=..., 
    aId=...)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:77
#11 0x0000007fb88c13d0 in mozilla::layers::PCompositorBridgeParent::
    OnMessageReceived (this=0x7f8c99d3f0, msg__=...)
    at PCompositorBridgeParent.cpp:1391
[...]
#27 0x0000007fbe70d89c in ?? () from /lib64/libc.so.6
(gdb) 

PLayerTransactionParent*
EmbedLiteCompositorBridgeParent::AllocPLayerTransactionParent
    (const nsTArray<LayersBackend>& aBackendHints, const LayersId& aId)
{
  PLayerTransactionParent* p =
    CompositorBridgeParent::AllocPLayerTransactionParent(aBackendHints, aId);

  EmbedLiteWindowParent *parentWindow = EmbedLiteWindowParent::From(mWindowId);
  if (parentWindow) {
    parentWindow->GetListener()->CompositorCreated();
  }

  if (!StaticPrefs::embedlite_compositor_external_gl_context()) {
    // Prepare Offscreen rendering context
    PrepareOffscreen();
  }
  return p;
}

    SwapChain* swapChain = context->GetSwapChain();
    if (swapChain == nullptr) {
      swapChain = new SwapChain();
      new SwapChainPresenter(*swapChain);
      context->mSwapChain.reset(swapChain);

      bool success = context->ResizeScreenBuffer(mEGLSurfaceSize);
      if (!success) {
          NS_WARNING("Failed to create SwapChain back buffer");
      }
    }

$ gdb harbour-webview
GNU gdb (GDB) Mer (8.2.1+git9)
[...]
=============== Preparing offscreen rendering context ===============

Thread 36 "Compositor" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 16991]
mozilla::gl::SwapChain::Resize (this=0x7ed81ce090, size=...)
    at gfx/gl/GLScreenBuffer.cpp:134
134           mFactory->CreateShared(size);
(gdb) bt
#0  mozilla::gl::SwapChain::Resize (this=0x7ed81ce090, size=...)
    at gfx/gl/GLScreenBuffer.cpp:134
#1  0x0000007ff110dc14 in mozilla::gl::GLContext::ResizeScreenBuffer
    (this=this@entry=0x7ed819ee40, size=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
#2  0x0000007ff366824c in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    PrepareOffscreen (this=this@entry=0x7fc4bef570)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:132
#3  0x0000007ff36682b8 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    AllocPLayerTransactionParent (this=0x7fc4bef570, aBackendHints=..., aId=...)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:90
#4  0x0000007ff0c65ad0 in mozilla::layers::PCompositorBridgeParent::
    OnMessageReceived (this=0x7fc4bef570, msg__=...)
    at PCompositorBridgeParent.cpp:1285
[...]
#19 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) p size.width
$2 = 1080
(gdb) p size.height
$3 = 2520
(gdb) p mFactory.mTuple.mFirstA
$5 = (mozilla::gl::SurfaceFactory *) 0x0
(gdb) 

bool SwapChain::Resize(const gfx::IntSize& size) {
  UniquePtr<SharedSurface> newBack =
      mFactory->CreateShared(size);
  if (!newBack) return false;

  if (mPresenter->mBackBuffer) mPresenter->mBackBuffer->ProducerRelease();

  mPresenter->mBackBuffer.reset(newBack.release());

  mPresenter->mBackBuffer->ProducerAcquire();

  return true;
}

  if (context->IsOffscreen()) {
    UniquePtr<SurfaceFactory> factory;
    if (context->GetContextType() == GLContextType::EGL) {
      // [Basic/OGL Layers, OMTC] WebGL layer init.
      factory = SurfaceFactory_EGLImage::Create(*context);
    } else {
      // [Basic Layers, OMTC] WebGL layer init.
      // Well, this *should* work...
      factory = MakeUnique<SurfaceFactory_Basic>(*context);
    }

    SwapChain* swapChain = context->GetSwapChain();
    if (swapChain == nullptr) {
      swapChain = new SwapChain();
      new SwapChainPresenter(*swapChain);
      context->mSwapChain.reset(swapChain);
    }

    if (factory) {
      swapChain->Morph(std::move(factory));
    }
  }

  bool initSwapChain = false;
  // TODO: The switch from GLSCreenBuffer to SwapChain needs completing
  // See: https://phabricator.services.mozilla.com/D75055
  if (context->IsOffscreen()) {
[...]
    SwapChain* swapChain = context->GetSwapChain();
    if (swapChain == nullptr) {
      initSwapChain = true;
      swapChain = new SwapChain();
      new SwapChainPresenter(*swapChain);
      context->mSwapChain.reset(swapChain);
    }

    if (factory) {
      swapChain->Morph(std::move(factory));
    }

    if (initSwapChain) {
      bool success = context->ResizeScreenBuffer(mEGLSurfaceSize);
      if (!success) {
          NS_WARNING("Failed to create SwapChain back buffer");
      }
    }
  }

$ time harbour-webview 
[D] unknown:0 - QML debugging is enabled. Only use this in a safe environment.
[D] main:30 - WebView Example
[D] main:44 - Using default start URL:  "https://www.flypig.co.uk/search/"
[D] main:47 - Opening webview
[D] unknown:0 - Using Wayland-EGL
library "libutils.so" not found
[...]
JSComp: UserAgentOverrideHelper.js loaded
UserAgentOverrideHelper app-startup
CONSOLE message:
[JavaScript Error: "Unexpected event profile-after-change"
    {file: "resource://gre/modules/URLQueryStrippingListService.jsm" line: 228}]
observe@resource://gre/modules/URLQueryStrippingListService.jsm:228:12

Created LOG for EmbedPrefs
Created LOG for EmbedLiteLayerManager
Command terminated by signal 11
real    0m 20.82s
user    0m 0.87s
sys     0m 0.23s

$ gdb harbour-webview 
GNU gdb (GDB) Mer (8.2.1+git9)
[...]
(gdb) r
Starting program: /usr/bin/harbour-webview 
[...]
Thread 37 "Compositor" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 18684]
mozilla::gl::SwapChain::Resize (this=0x0, size=...)
    at gfx/gl/GLScreenBuffer.cpp:134
134           mFactory->CreateShared(size);
(gdb) bt
#0  mozilla::gl::SwapChain::Resize (this=0x0, size=...)
    at gfx/gl/GLScreenBuffer.cpp:134
#1  0x0000007ff110dc14 in mozilla::gl::GLContext::ResizeScreenBuffer
    (this=this@entry=0x7edc19ee40, size=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
#2  0x0000007ff119b8d4 in mozilla::layers::CompositorOGL::CreateContext
    (this=this@entry=0x7edc002f10)
    at gfx/layers/opengl/CompositorOGL.cpp:264
#3  0x0000007ff11b0ea8 in mozilla::layers::CompositorOGL::Initialize
    (this=0x7edc002f10, out_failureReason=0x7f17aac520)
    at gfx/layers/opengl/CompositorOGL.cpp:394
#4  0x0000007ff12c68e8 in mozilla::layers::CompositorBridgeParent::NewCompositor
    (this=this@entry=0x7fc4b7b450, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1493
#5  0x0000007ff12d1964 in mozilla::layers::CompositorBridgeParent::
    InitializeLayerManager (this=this@entry=0x7fc4b7b450, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1436
#6  0x0000007ff12d1a94 in mozilla::layers::CompositorBridgeParent::
    AllocPLayerTransactionParent (this=this@entry=0x7fc4b7b450,
    aBackendHints=..., aId=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1546
#7  0x0000007ff36682b8 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    AllocPLayerTransactionParent (this=0x7fc4b7b450, aBackendHints=..., 
    aId=...)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:80
#8  0x0000007ff0c65ad0 in mozilla::layers::PCompositorBridgeParent::
    OnMessageReceived (this=0x7fc4b7b450, msg__=...)
    at PCompositorBridgeParent.cpp:1285
#9  0x0000007ff0ca9fe4 in mozilla::layers::PCompositorManagerParent::
    OnMessageReceived (this=<optimized out>, msg__=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/ipc/
    ProtocolUtils.h:675
#10 0x0000007ff0bc985c in mozilla::ipc::MessageChannel::DispatchAsyncMessage
    (this=this@entry=0x7fc4d82fb8, aProxy=aProxy@entry=0x7edc002aa0, aMsg=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/ipc/
    ProtocolUtils.h:675
[...]
#23 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) 

bool SwapChain::Resize(const gfx::IntSize& size) {
  UniquePtr<SharedSurface> newBack =
      mFactory->CreateShared(size);
[...]
}

(gdb) p mFactory
Cannot access memory at address 0x8
(gdb) frame 1
#1  0x0000007ff110dc14 in mozilla::gl::GLContext::ResizeScreenBuffer
    (this=this@entry=0x7edc19ee40, size=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
290     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:
    No such file or directory.
(gdb) p mSwapChain
Cannot access memory at address 0x7edc19f838
(gdb) p this
$1 = (mozilla::gl::GLContext * const) 0x7edc19ee40
(gdb) frame 2
#2  0x0000007ff119b8d4 in mozilla::layers::CompositorOGL::CreateContext
    (this=this@entry=0x7edc002f10)
    at gfx/layers/opengl/CompositorOGL.cpp:264
264       bool success = context->ResizeScreenBuffer(mSurfaceSize);
(gdb) p context
$2 = {mRawPtr = 0x7edc19ee40}
(gdb) p context->mRawPtr
Attempt to take address of value not located in memory.
(gdb) p context->mRawPtr->mSwapChain
Attempt to take address of value not located in memory.

(gdb) b GLContext::ResizeScreenBuffer
Breakpoint 1 at 0x7ff110dbdc: file gf
x/gl/GLContext.cpp, line 1885.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview
[...]
Thread 37 "Compositor" hit Breakpoint 1, mozilla::gl::GLContext::
    ResizeScreenBuffer (this=this@entry=0x7ed419ee40, size=...)
    at gfx/gl/GLContext.cpp:1885
1885    bool GLContext::ResizeScreenBuffer(const gfx::IntSize& size) {
(gdb) c
Continuing.

Thread 37 "Compositor" received signal SIGSEGV, Segmentation fault.
mozilla::gl::SwapChain::Resize (this=0x0, size=...)
    at gfx/gl/GLScreenBuffer.cpp:134
134           mFactory->CreateShared(size);
(gdb)                            

(gdb) b CompositorOGL::CreateContext
Breakpoint 2 at 0x7ff119b764: file gfx/layers/opengl/CompositorOGL.cpp,
    line 227.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]

Thread 37 "Compositor" hit Breakpoint 2, mozilla::layers::CompositorOGL::
    CreateContext (this=this@entry=0x7edc002ed0)
    at gfx/layers/opengl/CompositorOG
L.cpp:227
227     already_AddRefed<mozilla::gl::GLContext> CompositorOGL::CreateContext() {
(gdb) p context
$3 = <optimized out>
(gdb) p mSwapChain
No symbol "mSwapChain" in current context.
(gdb) p context
$4 = <optimized out>
(gdb) bt
#0  mozilla::layers::CompositorOGL::CreateContext (this=this@entry=0x7edc002ed0)
    at gfx/layers/opengl/CompositorOG
L.cpp:227
#1  0x0000007ff11b0ea8 in mozilla::layers::CompositorOGL::Initialize
    (this=0x7edc002ed0, out_failureReason=0x7f17a6b520)
    at gfx/layers/opengl/CompositorOGL.cpp:394
#2  0x0000007ff12c68e8 in mozilla::layers::CompositorBridgeParent::NewCompositor
    (this=this@entry=0x7fc4beb0e0, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1493
#3  0x0000007ff12d1964 in mozilla::layers::CompositorBridgeParent::
    InitializeLayerManager (this=this@entry=0x7fc4beb0e0, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1436
#4  0x0000007ff12d1a94 in mozilla::layers::CompositorBridgeParent::
    AllocPLayerTransactionParent (this=this@entry=0x7fc4beb0e0,
    aBackendHints=..., aId=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1546
#5  0x0000007ff36682b8 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    AllocPLayerTransactionParent (this=0x7fc4beb0e0, aBackendHints=..., aId=...)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:80
#6  0x0000007ff0c65ad0 in mozilla::layers::PCompositorBridgeParent::
    OnMessageReceived (this=0x7fc4beb0e0, msg__=...)
    at PCompositorBridgeParent.cpp:1285
[...]
#21 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) n
[New LWP 32378]
231       nsIWidget* widget = mWidget->RealWidget();
(gdb) n
[New LWP 32389]
[LWP 7850 exited]
232       void* widgetOpenGLContext =
(gdb) n
[New LWP 32476]
[LWP 32389 exited]
234       if (widgetOpenGLContext) {
(gdb) n
248       if (!context && gfxEnv::LayersPreferOffscreen()) {
(gdb) n
249         nsCString discardFailureId;
(gdb) n
250         context = GLContextProvider::CreateHeadless(
(gdb) n
252         if (!context->CreateOffscreenDefaultFb(mSurfaceSize)) {
(gdb) n
249         nsCString discardFailureId;
(gdb) n
257       if (!context) {
(gdb) n
264       bool success = context->ResizeScreenBuffer(mSurfaceSize);
(gdb) p context
$7 = {mRawPtr = 0x7edc19ee40}
(gdb) p context.mRawPtr
$8 = (mozilla::gl::GLContext *) 0x7edc19ee40
(gdb) p context.mRawPtr.mSwapChain
$9 = {
  mTuple = {<mozilla::detail::CompactPairHelper<mozilla::gl::SwapChain*, mozilla::DefaultDelete<mozilla::gl::SwapChain>, (mozilla::detail::StorageType)1, (mozilla::detail::StorageType)0>> = {<mozilla::DefaultDelete<mozilla::gl::SwapChain>> = {<No data fields>}, mFirstA = 0x0}, <No data fields>}}
(gdb) p context.mRawPtr.mSwapChain.mTuple.mFirstA
$10 = (mozilla::gl::SwapChain *) 0x0
(gdb)

(gdb) b EmbedLiteCompositorBridgeParent::PrepareOffscreen
Breakpoint 3 at 0x7ff366810c: file mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp, line 104.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 36 "Compositor" hit Breakpoint 2, mozilla::layers::CompositorOGL::
    CreateContext (this=this@entry=0x7ed8002da0)
    at gfx/layers/opengl/CompositorOGL.cpp:227
227     already_AddRefed<mozilla::gl::GLContext> CompositorOGL::
    CreateContext() {
(gdb) 

$ git log -1 -S "GLContextProviderEGL::CreateOffscreen" \
    gecko-dev/gfx/gl/GLContextProviderEGL.cpp
commit 4232c2c466220d42223443bd5bd2f3c849123380
Author: Jeff Gilbert <jgilbert@mozilla.com>
Date:   Mon Jun 15 18:26:12 2020 +0000

    Bug 1632249 - Replace GLContextProvider::CreateOffscreen with
    GLContext::CreateOffscreenDefaultFb. r=lsalzman
    
    Differential Revision: https://phabricator.services.mozilla.com/D79390

(gdb) delete break
Delete all breakpoints? (y or n) y
(gdb) b GLContextProviderEGL::CreateOffscreen Breakpoint 6 at 0x7fb8e839f0:
    file gfx/gl/GLContextProviderEGL.cpp, line 1400.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 36 "Compositor" hit Breakpoint 6, mozilla::gl::GLContextProviderEGL::
    CreateOffscreen (size=..., minCaps=..., 
    flags=flags@entry=mozilla::gl::CreateContextFlags::REQUIRE_COMPAT_PROFILE,
    out_failureId=out_failureId@entry=0x7fa516f378)
    at gfx/gl/GLContextProviderEGL.cpp:1400
1400        CreateContextFlags flags, nsACString* const out_failureId) {
(gdb) bt
#0  mozilla::gl::GLContextProviderEGL::CreateOffscreen (size=..., minCaps=..., flags=flags@entry=mozilla::gl::CreateContextFlags::REQUIRE_COMPAT_PROFILE, 
    out_failureId=out_failureId@entry=0x7fa516f378)
    at gfx/gl/GLContextProviderEGL.cpp:1400
#1  0x0000007fb8ee475c in mozilla::layers::CompositorOGL::CreateContext
    (this=0x7eac003420)
    at gfx/layers/opengl/CompositorOGL.cpp:250
#2  mozilla::layers::CompositorOGL::CreateContext (this=0x7eac003420)
    at gfx/layers/opengl/CompositorOGL.cpp:223
#3  0x0000007fb8f053bc in mozilla::layers::CompositorOGL::Initialize
    (this=0x7eac003420, out_failureReason=0x7fa516f730)
    at gfx/layers/opengl/CompositorOGL.cpp:374
#4  0x0000007fb8fdcf7c in mozilla::layers::CompositorBridgeParent::NewCompositor
    (this=this@entry=0x7f8c99dc60, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1534
#5  0x0000007fb8fe65e8 in mozilla::layers::CompositorBridgeParent::
    InitializeLayerManager (this=this@entry=0x7f8c99dc60, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1491
#6  0x0000007fb8fe6730 in mozilla::layers::CompositorBridgeParent::
    AllocPLayerTransactionParent (this=this@entry=0x7f8c99dc60,
    aBackendHints=..., aId=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1587
#7  0x0000007fbb2e31b4 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    AllocPLayerTransactionParent (this=0x7f8c99dc60, aBackendHints=..., 
    aId=...) at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:77
#8  0x0000007fb88c13d0 in mozilla::layers::PCompositorBridgeParent::
    OnMessageReceived (this=0x7f8c99dc60, msg__=...)
    at PCompositorBridgeParent.cpp:1391
#9  0x0000007fb88f86ac in mozilla::layers::PCompositorManagerParent::
    OnMessageReceived (this=<optimized out>, msg__=...)
    at obj-build-mer-qt-xr/dist/include/mozilla/ipc/ProtocolUtils.h:866
[...]
#24 0x0000007fbe70d89c in ?? () from /lib64/libc.so.6
(gdb) 

  // Allow to create offscreen GL context for main Layer Manager
  if (!context && gfxEnv::LayersPreferOffscreen()) {
    SurfaceCaps caps = SurfaceCaps::ForRGB();
    caps.preserve = false;
    caps.bpp16 = gfxVars::OffscreenFormat() == SurfaceFormat::R5G6B5_UINT16;

    nsCString discardFailureId;
    context = GLContextProvider::CreateOffscreen(
        mSurfaceSize, caps, CreateContextFlags::REQUIRE_COMPAT_PROFILE,
        &discardFailureId);
  }

  // Allow to create offscreen GL context for main Layer Manager
  if (!context && gfxEnv::LayersPreferOffscreen()) {
    nsCString discardFailureId;
    context = GLContextProvider::CreateHeadless(
        {CreateContextFlags::REQUIRE_COMPAT_PROFILE}, &discardFailureId);
    if (!context->CreateOffscreenDefaultFb(mSurfaceSize)) {
      context = nullptr;
    }
  }

(gdb) delete break
(gdb) b EmbedLiteCompositorBridgeParent::CompositeToDefaultTarget
Breakpoint 3 at 0x7ff3667880: EmbedLiteCompositorBridgeParent::
    CompositeToDefaultTarget. (2 locations)
(gdb) b GLContextProviderEGL::CreateHeadless
Breakpoint 4 at 0x7ff1133740: file gfx/gl/GLContextProviderEGL.cpp, line 1245.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 36 "Compositor" hit Breakpoint 4, mozilla::gl::GLContextProviderEGL::
    CreateHeadless (desc=..., out_failureId=out_failureId@entry=0x7f1faad1c8)
    at gfx/gl/GLContextProviderEGL.cpp:1245
1245        const GLContextCreateDesc& desc, nsACString* const out_failureId) {
(gdb) bt
#0  mozilla::gl::GLContextProviderEGL::CreateHeadless (desc=...,
    out_failureId=out_failureId@entry=0x7f1faad1c8)
    at gfx/gl/GLContextProviderEGL.cpp:1245
#1  0x0000007ff119b81c in mozilla::layers::CompositorOGL::CreateContext
    (this=this@entry=0x7ee0002f50)
    at gfx/layers/opengl/CompositorOGL.cpp:250
#2  0x0000007ff11b0e24 in mozilla::layers::CompositorOGL::Initialize
    (this=0x7ee0002f50, out_failureReason=0x7f1faad520)
    at gfx/layers/opengl/CompositorOGL.cpp:389
#3  0x0000007ff12c6864 in mozilla::layers::CompositorBridgeParent::
    NewCompositor (this=this@entry=0x7fc4b3d260, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1493
#4  0x0000007ff12d18e0 in mozilla::layers::CompositorBridgeParent::
    InitializeLayerManager (this=this@entry=0x7fc4b3d260, aBackendHints=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1436
#5  0x0000007ff12d1a10 in mozilla::layers::CompositorBridgeParent::
    AllocPLayerTransactionParent (this=this@entry=0x7fc4b3d260,
    aBackendHints=..., aId=...)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:1546
#6  0x0000007ff3668238 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    AllocPLayerTransactionParent (this=0x7fc4b3d260, aBackendHints=..., aId=...)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:80
#7  0x0000007ff0c65ad0 in mozilla::layers::PCompositorBridgeParent::
    OnMessageReceived (this=0x7fc4b3d260, msg__=...)
    at PCompositorBridgeParent.cpp:1285
#8  0x0000007ff0ca9fe4 in mozilla::layers::PCompositorManagerParent::
    OnMessageReceived (this=<optimized out>, msg__=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/ipc/
    ProtocolUtils.h:675
[...]
#22 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) c
Continuing.
[New LWP 2694]
=============== Preparing offscreen rendering context ===============
[New LWP 2695]

Thread 36 "Compositor" hit Breakpoint 3, non-virtual thunk to mozilla::embedlite::EmbedLiteCompositorBridgeParent::CompositeToDefaultTarget
    (mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>) ()
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.h:58
58        virtual void CompositeToDefaultTarget(VsyncId aId) override;
(gdb) bt
#0  non-virtual thunk to mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    CompositeToDefaultTarget(mozilla::layers::BaseTransactionId
    <mozilla::VsyncIdType>) ()
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.h:58
#1  0x0000007ff12b808c in mozilla::layers::CompositorVsyncScheduler::
    ForceComposeToTarget (this=0x7fc4d0df60, aTarget=aTarget@entry=0x0, 
    aRect=aRect@entry=0x0)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/
    LayersTypes.h:82
#2  0x0000007ff12b80e8 in mozilla::layers::CompositorBridgeParent::
    ResumeComposition (this=this@entry=0x7fc4b3d260)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/RefPtr.h:313
#3  0x0000007ff12b8174 in mozilla::layers::CompositorBridgeParent::
    ResumeCompositionAndResize (this=0x7fc4b3d260, x=<optimized out>,
    y=<optimized out>, width=<optimized out>, height=<optimized out>)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:794
#4  0x0000007ff12b0d10 in mozilla::detail::RunnableMethodArguments<int,
    int, int, int>::applyImpl<mozilla::layers::CompositorBridgeParent, void
    (mozilla::layers::CompositorBridgeParent::*)(int, int, int, int),
    StoreCopyPassByConstLRef<int>, StoreCopyPassByConstLRef<int>,
    StoreCopyPassByConstLRef<int>, StoreCopyPassByConstLRef<int>, 0ul, 1ul, 2ul,
    3ul> (args=..., m=<optimized out>, o=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1151
[...]
#16 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) 

class GLContext 
public:
    UniquePtr<SwapChain> mSwapChain;
}

class GLContextEGL final : public GLContext {
}

void EmbedLiteCompositorBridgeParent::PrepareOffscreen() {
    const CompositorBridgeParent::LayerTreeState* state =
    CompositorBridgeParent::GetIndirectShadowTree(RootLayerTreeId());
    GLContext* context = static_cast<CompositorOGL*>(state->mLayerManager->
    GetCompositor())->gl();

    swapChain = new SwapChain();
    new SwapChainPresenter(*swapChain);
    context->mSwapChain.reset(swapChain);
}

already_AddRefed<mozilla::gl::GLContext> CompositorOGL::CreateContext() {
    context = GLContextProvider::CreateHeadless({CreateContextFlags::
    REQUIRE_COMPAT_PROFILE}, &discardFailureId);
    // Here we have access to context->mSwapChain;
}

  bool success = context->ResizeScreenBuffer(mSurfaceSize);
  if (!success) {
      NS_WARNING("Failed to create SwapChain back buffer");
  }

std::shared_ptr<SharedSurface> SwapChainPresenter::SwapBackBuffer(
    std::shared_ptr<SharedSurface> back) {
[...]
  auto old = mBackBuffer;
  mBackBuffer = back;
  if (mBackBuffer) {
    mBackBuffer->WaitForBufferOwnership();
    mBackBuffer->ProducerAcquire();
    mBackBuffer->LockProd();
  }
  return old;
}

bool SwapChain::Resize(const gfx::IntSize& size) {
  UniquePtr<SharedSurface> newBack =
      mFactory->CreateShared(size);
  if (!newBack) return false;

  if (mPresenter->mBackBuffer) mPresenter->mBackBuffer->ProducerRelease();

  mPresenter->mBackBuffer.reset(newBack.release());

  mPresenter->mBackBuffer->ProducerAcquire();

  return true;
}

(gdb) delete break
(gdb) b SwapChainPresenter::SwapBackBuffer
Breakpoint 1 at 0x7ff1109c14: file gfx/gl/GLScreenBuffer.cpp, line 82.
(gdb) b SwapChain::Resize
Breakpoint 2 at 0x7ff110a398: file gfx/gl/GLScreenBuffer.cpp, line 132.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]

Thread 37 "Compositor" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 4362]
0x0000007ff110a38c in mozilla::gl::SwapChain::OffscreenSize
    (this=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
290     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:
    No such file or directory.
(gdb) frame 1
#1  0x0000007ff3667930 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    CompositeToDefaultTarget (this=0x7fc4b3f070, aId=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
290     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:
    No such file or directory.
(gdb) p context->mSwapChain.mTuple.mFirstA->mPresenter->mBackBuffer
$1 = std::shared_ptr<mozilla::gl::SharedSurface> (empty) = {get() = 0x0}
(gdb) 

1. The SwapChain is created in EmbedLiteCompositorBridgeParent::PrepareOffscreen().
2. The SwapChainPresenter() is created immediately afterwards.
3. In EmbedLiteCompositorBridgeParent::CompositeToDefaultTarget() the SwapChain::OffscreenSize() method is called, causing the crash.
4. Immediately after this SwapChain::Resize() is called, which if done earlier, would prevent the crash.

    if (context->GetSwapChain()->OffscreenSize() != mEGLSurfaceSize
      && !context->GetSwapChain()->Resize(mEGLSurfaceSize)) {
      return;
    }

$ git blame \
    embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp \
    -L 153,156
^01b1a0352034 embedthread/EmbedLiteCompositorBridgeParent.cpp
    (Raine Makelainen  2020-07-24 16:25:17 +0300 153)
    MutexAutoLock lock(mRenderMutex);
d59d44a5bccaf embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp
    (David Llewellyn-Jones 2023-09-04 09:03:49 +0100 154)
    if (context->GetSwapChain()->OffscreenSize() != mEGLSurfaceSize
d59d44a5bccaf embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp
    (David Llewellyn-Jones 2023-09-04 09:03:49 +0100 155)
    && !context->GetSwapChain()->Resize(mEGLSurfaceSize)) {
^01b1a0352034 embedthread/EmbedLiteCompositorBridgeParent.cpp
    (Raine Makelainen      2020-07-24 16:25:17 +0300 156)
    return;

$ git diff d59d44a5bccaf~ d59d44a5bccaf

@@ -153,7 +157,8 @@ EmbedLiteCompositorBridgeParent::CompositeToDefaultTarget
    (VsyncId aId)
[...] 
   if (context->IsOffscreen()) {
     MutexAutoLock lock(mRenderMutex);
-    if (context->OffscreenSize() != mEGLSurfaceSize && !context->
    ResizeOffscreen(mEGLSurfaceSize)) {
+    if (context->GetSwapChain()->OffscreenSize() != mEGLSurfaceSize
+      && !context->GetSwapChain()->Resize(mEGLSurfaceSize)) {
       return;
     }
   }

$ git blame gfx/gl/GLScreenBuffer.cpp -L 128,130
f536dbf9f6f8a (David Llewellyn-Jones 2023-09-04 08:52:00 +0100 128)
    const gfx::IntSize& SwapChain::OffscreenSize() const {
f536dbf9f6f8a (David Llewellyn-Jones 2023-09-04 08:52:00 +0100 129)
      return mPresenter->mBackBuffer->mFb->mSize;
f536dbf9f6f8a (David Llewellyn-Jones 2023-09-04 08:52:00 +0100 130)
    }

diff --git a/gfx/gl/GLScreenBuffer.cpp b/gfx/gl/GLScreenBuffer.cpp
index 0398dd7dc6a2..e71263068777 100644
--- a/gfx/gl/GLScreenBuffer.cpp
+++ b/gfx/gl/GLScreenBuffer.cpp
@@ -116,4 +116,38 @@ SwapChain::~SwapChain() {
   }
 }
 
[...]
+
+const gfx::IntSize& SwapChain::OffscreenSize() const {
+  return mPresenter->mBackBuffer->mFb->mSize;
+}
+
[...]

const gfx::IntSize& GLContext::OffscreenSize() const {
  MOZ_ASSERT(IsOffscreen());
  return mScreen->Size();
}

bool GLContext::CreateScreenBufferImpl(const IntSize& size,
                                       const SurfaceCaps& caps) {
  UniquePtr<GLScreenBuffer> newScreen =
      GLScreenBuffer::Create(this, size, caps);
  if (!newScreen) return false;

  if (!newScreen->Resize(size)) {
    return false;
  }

  // This will rebind to 0 (Screen) if needed when
  // it falls out of scope.
  ScopedBindFramebuffer autoFB(this);

  mScreen = std::move(newScreen);

  return true;
}

bool GLContext::InitOffscreen(const gfx::IntSize& size,
                              const SurfaceCaps& caps) {
  if (!CreateScreenBuffer(size, caps)) return false;
[...]

already_AddRefed<GLContext> GLContextProviderCGL::CreateOffscreen(
    const IntSize& size,
    const SurfaceCaps& minCaps,
    CreateContextFlags flags,
    nsACString* const out_failureId) {
  RefPtr<GLContext> gl = CreateHeadless(flags, out_failureId);
  if (!gl) {
    return nullptr;
  }

  if (!gl->InitOffscreen(size, minCaps)) {
    *out_failureId = NS_LITERAL_CSTRING("FEATURE_FAILURE_CGL_INIT");
    return nullptr;
  }

  return gl.forget();
}

$ grep -rIn "new SwapChain(" *
embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp:128:
    swapChain = new SwapChain();
gecko-dev/dom/webgpu/CanvasContext.cpp:95:
    mSwapChain = new SwapChain(aDesc, extent, mExternalImageId, format);
gecko-dev/dom/webgpu/CanvasContext.cpp:139:
    mSwapChain = new SwapChain(desc, extent, mExternalImageId, gfxFormat);

$ git blame \
    embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp \
    -L 128,128
d59d44a5bccaf (David Llewellyn-Jones 2023-09-04 09:03:49 +0100 128)
    swapChain = new SwapChain();

$ git blame \\
    embedding/embedlite/embedthread/EmbedLiteCompositorBridgeParent.cpp \\
    -L 113,114
d59d44a5bccaf (David Llewellyn-Jones 2023-09-04 09:03:49 +0100 113)
    // TODO: The switch from GLSCreenBuffer to SwapChain needs completing
d59d44a5bccaf (David Llewellyn-Jones 2023-09-04 09:03:49 +0100 114)
    // See: https://phabricator.services.mozilla.com/D75055

void
EmbedLiteCompositorBridgeParent::PrepareOffscreen()
{
  fprintf(stderr,
      "=============== Preparing offscreen rendering context ===============\n");

  const CompositorBridgeParent::LayerTreeState* state =
      CompositorBridgeParent::GetIndirectShadowTree(RootLayerTreeId());
  NS_ENSURE_TRUE(state && state->mLayerManager, );

  GLContext* context = static_cast<CompositorOGL*>(state->mLayerManager->
      GetCompositor())->gl();
  NS_ENSURE_TRUE(context, );

  // TODO: The switch from GLSCreenBuffer to SwapChain needs completing
  // See: https://phabricator.services.mozilla.com/D75055
  if (context->IsOffscreen()) {
    UniquePtr<SurfaceFactory> factory;
    if (context->GetContextType() == GLContextType::EGL) {
      // [Basic/OGL Layers, OMTC] WebGL layer init.
      factory = SurfaceFactory_EGLImage::Create(*context);
    } else {
      // [Basic Layers, OMTC] WebGL layer init.
      // Well, this *should* work...
      factory = MakeUnique<SurfaceFactory_Basic>(*context);
    }

    SwapChain* swapChain = context->GetSwapChain();
    if (swapChain == nullptr) {
      swapChain = new SwapChain();
      new SwapChainPresenter(*swapChain);
      context->mSwapChain.reset(swapChain);
    }

    if (factory) {
      swapChain->Morph(std::move(factory));
    }
  }
}

(gdb) delete break
Delete all breakpoints? (y or n) y
(gdb) b EmbedLiteCompositorBridgeParent::PrepareOffscreen
Breakpoint 10 at 0x7ff366808c: file mobile/sailfishos/embedthread/
    EmbedLiteCompositorBridgeParent.cpp, line 104.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]

Thread 36 "Compositor" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 14342]
mozilla::gl::SwapChain::OffscreenSize (this=0x0)
    at gfx/gl/GLScreenBuffer.cpp:129
129       return mPresenter->mBackBuffer->mFb->mSize;
(gdb) bt
#0  mozilla::gl::SwapChain::OffscreenSize (this=0x0)
    at gfx/gl/GLScreenBuffer.cpp:129
#1  0x0000007ff3667930 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    CompositeToDefaultTarget (this=0x7fc4aebc90, aId=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
#2  0x0000007ff12b808c in mozilla::layers::CompositorVsyncScheduler::
    ForceComposeToTarget (this=0x7fc4d0b230, aTarget=aTarget@entry=0x0, 
    aRect=aRect@entry=0x0)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/LayersTypes.h:82
#3  0x0000007ff12b80e8 in mozilla::layers::CompositorBridgeParent::
    ResumeComposition (this=this@entry=0x7fc4aebc90)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/RefPtr.h:313
#4  0x0000007ff12b8174 in mozilla::layers::CompositorBridgeParent::
    ResumeCompositionAndResize (this=0x7fc4aebc90, x=<optimized out>,
    y=<optimized out>, width=<optimized out>, height=<optimized out>)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:794
#5  0x0000007ff12b0d10 in mozilla::detail::RunnableMethodArguments<int, int,
    int, int>::applyImpl<mozilla::layers::CompositorBridgeParent, void
    (mozilla::layers::CompositorBridgeParent::*)(int, int, int, int),
    StoreCopyPassByConstLRef<int>, StoreCopyPassByConstLRef<int>,
    StoreCopyPassByConstLRef<int>, StoreCopyPassByConstLRef<int>, 0ul, 1ul,
    2ul, 3ul> (args=..., m=<optimized out>, o=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1151
#6  mozilla::detail::RunnableMethodArguments<int, int, int, int>::apply
    <mozilla::layers::CompositorBridgeParent, void (mozilla::layers::
    CompositorBridgeParent::*)(int, int, int, int)> (m=<optimized out>,
    o=<optimized out>, this=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1154
[...]
#17 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) 

  if (!StaticPrefs::embedlite_compositor_external_gl_context()) {
    // Prepare Offscreen rendering context
    PrepareOffscreen();
  }

Thread 36 "Compositor" hit Breakpoint 11, mozilla::embedlite::
    EmbedLiteCompositorBridgeParent::AllocPLayerTransactionParent
    (this=0x7fc4bc68c0, aBackendHints=..., aId=...)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:79
79      {
(gdb) n
80        PLayerTransactionParent* p =
(gdb) n
83        EmbedLiteWindowParent *parentWindow = EmbedLiteWindowParent::From(mWindowId);
(gdb) n
84        if (parentWindow) {
(gdb) n
85          parentWindow->GetListener()->CompositorCreated();
(gdb) n
88        if (!StaticPrefs::embedlite_compositor_external_gl_context()) {
(gdb) n
mozilla::layers::PCompositorBridgeParent::OnMessageReceived
    (this=0x7fc4bc68c0, msg__=...) at PCompositorBridgeParent.cpp:1286
1286    PCompositorBridgeParent.cpp: No such file or directory.
(gdb) 

$ pushd ../sailfish-browser/
$ grep -rIn "embedlite.compositor.external_gl_context" *
apps/core/declarativewebutils.cpp:239:
    webEngineSettings->setPreference(QString(
    "embedlite.compositor.external_gl_context"), QVariant(true));
data/prefs.js:5:
    user_pref("embedlite.compositor.external_gl_context", true);
tests/auto/mocks/declarativewebutils/declarativewebutils.cpp:62:
    webEngineSettings->setPreference(QString(
    "embedlite.compositor.external_gl_context"), QVariant(true));
$ popd

diff --git a/lib/webenginesettings.cpp b/lib/webenginesettings.cpp
index de9e4b86..780f6555 100644
--- a/lib/webenginesettings.cpp
+++ b/lib/webenginesettings.cpp
@@ -110,6 +110,12 @@ void SailfishOS::WebEngineSettings::initialize()
     engineSettings->setPreference(QStringLiteral("intl.accept_languages"),
                                   QVariant::fromValue<QString>(langs));
 
+    // Ensure the renderer is configured correctly
+    engineSettings->setPreference(QStringLiteral("gfx.webrender.force-disabled"),
+                                  QVariant(true));
+    engineSettings->setPreference(QStringLiteral("embedlite.compositor.external_gl_context"),
+                                  QVariant(false));
+
     Silica::Theme *silicaTheme = Silica::Theme::instance();
 
     // Notify gecko when the ambience switches between light and dark

$ harbour-webview
[D] unknown:0 - QML debugging is enabled. Only use this in a safe environment.
[D] main:30 - WebView Example
[D] main:44 - Using default start URL:  "https://www.flypig.co.uk/search/"
[D] main:47 - Opening webview
[D] unknown:0 - Using Wayland-EGL
library "libutils.so" not found
[...]
JSComp: UserAgentOverrideHelper.js loaded
UserAgentOverrideHelper app-startup
CONSOLE message:
[JavaScript Error: "Unexpected event profile-after-change" {file:
    "resource://gre/modules/URLQueryStrippingListService.jsm" line: 228}]
observe@resource://gre/modules/URLQueryStrippingListService.jsm:228:12

Created LOG for EmbedPrefs
Created LOG for EmbedLiteLayerManager
=============== Preparing offscreen rendering context ===============
Segmentation fault

$ gdb harbour-webview 
GNU gdb (GDB) Mer (8.2.1+git9)
[...]
(gdb) b EmbedLiteCompositorBridgeParent::PrepareOffscreen
Function "EmbedLiteCompositorBridgeParent::PrepareOffscreen" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (EmbedLiteCompositorBridgeParent::PrepareOffscreen) pending.
(gdb) r
[...]
Thread 36 "Compositor" hit Breakpoint 1, mozilla::embedlite::
    EmbedLiteCompositorBridgeParent::PrepareOffscreen
    (this=this@entry=0x7fc4be7560)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:104
104     {
(gdb) n
[LWP 18280 exited]
105       fprintf(stderr,
    "=============== Preparing offscreen rendering context ===============\n");
(gdb) 
=============== Preparing offscreen rendering context ===============
107       const CompositorBridgeParent::LayerTreeState* state =
    CompositorBridgeParent::GetIndirectShadowTree(RootLayerTreeId());
(gdb) 
108       NS_ENSURE_TRUE(state && state->mLayerManager, );
(gdb) 
110       GLContext* context = static_cast<CompositorOGL*>
    (state->mLayerManager->GetCompositor())->gl();
(gdb) p context
$1 = <optimized out>
(gdb) n
111       NS_ENSURE_TRUE(context, );
(gdb) n
3540    ${PROJECT}/obj-build-mer-qt-xr/dist/include/GLContext.h:
    No such file or directory.
(gdb) n
117         if (context->GetContextType() == GLContextType::EGL) {
(gdb) n
119           factory = SurfaceFactory_EGLImage::Create(*context);
(gdb) n
126         SwapChain* swapChain = context->GetSwapChain();
(gdb) n
127         if (swapChain == nullptr) {
(gdb) n
128           swapChain = new SwapChain();
(gdb) n
129           new SwapChainPresenter(*swapChain);
(gdb) n
130           context->mSwapChain.reset(swapChain);
(gdb) n
133         if (factory) {
(gdb) n
134           swapChain->Morph(std::move(factory));
(gdb) n
mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    AllocPLayerTransactionParent (this=0x7fc4be7560, aBackendHints=..., aId=...)
    at mobile/sailfishos/embedthread/EmbedLiteCompositorBridgeParent.cpp:92
92        return p;
(gdb) c
Continuing.

Thread 36 "Compositor" received signal SIGSEGV, Segmentation fault.
0x0000007ff110a38c in mozilla::gl::SwapChain::OffscreenSize
    (this=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
290     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:
    No such file or directory.
(gdb) bt
#0  0x0000007ff110a38c in mozilla::gl::SwapChain::OffscreenSize
    (this=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
#1  0x0000007ff3667930 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    CompositeToDefaultTarget (this=0x7fc4be7560, aId=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
#2  0x0000007ff12b808c in mozilla::layers::CompositorVsyncScheduler::
    ForceComposeToTarget (this=0x7fc4d0b1a0, aTarget=aTarget@entry=0x0, 
    aRect=aRect@entry=0x0)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/
    LayersTypes.h:82
#3  0x0000007ff12b80e8 in mozilla::layers::CompositorBridgeParent::
    ResumeComposition (this=this@entry=0x7fc4be7560)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/RefPtr.h:313
#4  0x0000007ff12b8174 in mozilla::layers::CompositorBridgeParent::
    ResumeCompositionAndResize (this=0x7fc4be7560, x=<optimized out>,
    y=<optimized out>, width=<optimized out>, height=<optimized out>)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:794
#5  0x0000007ff12b0d10 in mozilla::detail::RunnableMethodArguments<int, int,
    int, int>::applyImpl<mozilla::layers::CompositorBridgeParent, void
    (mozilla::layers::CompositorBridgeParent::*)(int, int, int, int),
    StoreCopyPassByConstLRef<int>, StoreCopyPassByConstLRef<int>,
    StoreCopyPassByConstLRef<int>, StoreCopyPassByConstLRef<int>, 0ul, 1ul,
    2ul, 3ul> (args=..., m=<optimized out>, o=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1151
[...]
#17 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) 

const gfx::IntSize& SwapChain::OffscreenSize() const {
  return mPresenter->mBackBuffer->mFb->mSize;
}

(gdb) p mPresenter
value has been optimized out
(gdb) p this
$2 = <optimized out>

(gdb) frame 1
#1  0x0000007ff3667930 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    CompositeToDefaultTarget (this=0x7fc4be7560, aId=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
290     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:
    No such file or directory.
(gdb) p context
$3 = (mozilla::gl::GLContext *) 0x7ee019ee40
(gdb) p context->mSwapChain.mTuple.mFirstA
$5 = (mozilla::gl::SwapChain *) 0x7ee01ce090
(gdb) p context->mSwapChain.mTuple.mFirstA->mPresenter
$6 = (mozilla::gl::SwapChainPresenter *) 0x7ee01a1380
(gdb) p context->mSwapChain.mTuple.mFirstA->mPresenter->mBackBuffer
$7 = std::shared_ptr<mozilla::gl::SharedSurface> (empty) = {get() = 0x0}
(gdb) p context->mSwapChain.mTuple.mFirstA->mPresenter->mBackBuffer->mFb
Cannot access memory at address 0x20
(gdb) 

[W] unknown:7 - file:///usr/share/harbour-webview/qml/harbour-webview.qml:7:30:
    Type WebViewPage unavailable 
         initialPage: Component { WebViewPage { } } 
                                  ^
[W] unknown:13 - file:///usr/share/harbour-webview/qml/pages/
    WebViewPage.qml:13:5: Type WebView unavailable 
         WebView { 
         ^
[W] unknown:141 - file:///usr/lib64/qt5/qml/Sailfish/WebView/
    WebView.qml:141:9: Type TextSelectionController unavailable 
             TextSelectionController { 
             ^
[W] unknown:14 - file:///usr/lib64/qt5/qml/Sailfish/WebView/Controls/
    TextSelectionController.qml:14:1: module "QOfono" is not installed 
     import QOfono 0.2 
     ^

[W] unknown:14 - file:///usr/lib64/qt5/qml/Sailfish/WebView/Controls/
    TextSelectionController.qml:14:1: module "QOfono" is not installed 
     import QOfono 0.2 
     ^

diff --git a/rpm/sailfish-components-webview.spec
           b/rpm/sailfish-components-webview.spec
index 766933ba..c311ebcf 100644
--- a/rpm/sailfish-components-webview.spec
+++ b/rpm/sailfish-components-webview.spec
@@ -18,7 +18,7 @@ Requires: sailfishsilica-qt5 >= 1.1.123
 Requires: sailfish-components-media-qt5
 Requires: sailfish-components-pickers-qt5
 Requires: embedlite-components-qt5 >= 1.21.2
-Requires: libqofono-qt5-declarative >= 0.117
+Requires: libqofono-qt5-declarative >= 0.115
 
 %description
 %{summary}.

    readonly property bool _canCall: cellular1Status.registered
        || cellular2Status.registered

        isPhoneNumber = _canCall && _phoneNumberSelected

  _phoneRegex: /^\+?[0-9\s,-.\(\)*#pw]{1,30}$/,

  _getSelectedPhoneNumber: function sh_getSelectedPhoneNumber() {
    return this._isPhoneNumber(this._getSelectedText().trim());
  },

  _isPhoneNumber: function sh_isPhoneNumber(selectedText) {
    return (this._phoneRegex.test(selectedText) ? selectedText : null);
  },

$ git diff 16ef5cdf44c2eafd7d93e17a41927ef5da700c2b~ \
    16ef5cdf44c2eafd7d93e17a41927ef5da700c2b
diff --git a/import/controls/TextSelectionController.qml
           b/import/controls/TextSelectionController.qml
index 5c8f2845..71bd83cc 100644
--- a/import/controls/TextSelectionController.qml
+++ b/import/controls/TextSelectionController.qml
@@ -11,7 +11,7 @@
 
 import QtQuick 2.1
 import Sailfish.Silica 1.0
-import MeeGo.QOfono 0.2
+import QOfono 0.2
 
 MouseArea {
     id: root
diff --git a/rpm/sailfish-components-webview.spec
           b/rpm/sailfish-components-webview.spec
index 9a2a3154..5729a8d9 100644
--- a/rpm/sailfish-components-webview.spec
+++ b/rpm/sailfish-components-webview.spec
@@ -18,6 +18,7 @@ Requires: sailfishsilica-qt5 >= 1.1.123
 Requires: sailfish-components-media-qt5
 Requires: sailfish-components-pickers-qt5
 Requires: embedlite-components-qt5 >= 1.21.2
+Requires: libqofono-qt5-declarative >= 0.117
 
 %description
 %{summary}.

-import MeeGo.QOfono 0.2
+import QOfono 0.2

sed -i -e 's/QOfono/MeeGo.QOfono/g' \
    /usr/lib64/qt5/qml/Sailfish/WebView/Controls/TextSelectionController.qml

$ harbour-webview 
[D] unknown:0 - QML debugging is enabled. Only use this in a safe environment.
[...]
UserAgentOverrideHelper app-startup
CONSOLE message:
[JavaScript Error: "Unexpected event profile-after-change" {file:
    "resource://gre/modules/URLQueryStrippingListService.jsm" line: 228}]
observe@resource://gre/modules/URLQueryStrippingListService.jsm:228:12

Created LOG for EmbedPrefs
Created LOG for EmbedLiteLayerManager
Segmentation fault

$ gdb harbour-webview 
GNU gdb (GDB) Mer (8.2.1+git9)
[...]
Thread 36 "Compositor" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 24061]
mozilla::gl::SwapChain::OffscreenSize (this=0x0)
    at gfx/gl/GLScreenBuffer.cpp:129
129       return mPresenter->mBackBuffer->mFb->mSize;
(gdb) bt
#0  mozilla::gl::SwapChain::OffscreenSize (this=0x0)
    at gfx/gl/GLScreenBuffer.cpp:129
#1  0x0000007ff3667930 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    CompositeToDefaultTarget (this=0x7fc4be8da0, aId=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
#2  0x0000007ff12b808c in mozilla::layers::CompositorVsyncScheduler::
    ForceComposeToTarget (this=0x7fc4d0c0b0, aTarget=aTarget@entry=0x0, 
    aRect=aRect@entry=0x0)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/
    LayersTypes.h:82
#3  0x0000007ff12b80e8 in mozilla::layers::CompositorBridgeParent::
    ResumeComposition (this=this@entry=0x7fc4be8da0)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/RefPtr.h:313
#4  0x0000007ff12b8174 in mozilla::layers::CompositorBridgeParent::
    ResumeCompositionAndResize (this=0x7fc4be8da0, x=<optimized out>,
    y=<optimized out>, width=<optimized out>, height=<optimized out>)
    at gfx/layers/ipc/CompositorBridgeParent.cpp:794
#5  0x0000007ff12b0d10 in mozilla::detail::RunnableMethodArguments<int, int,
    int, int>::applyImpl<mozilla::layers::CompositorBridgeParent, void
    (mozilla::layers::CompositorBridgeParent::*)(int, int, int, int),
    StoreCopyPassByConstLRef<int>, StoreCopyPassByConstLRef<int>,
    StoreCopyPassByConstLRef<int>, StoreCopyPassByConstLRef<int>, 0ul, 1ul,
    2ul, 3ul> (args=..., m=<optimized out>, o=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1151
[...]
#17 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) 

const gfx::IntSize& SwapChain::OffscreenSize() const {
  return mPresenter->mBackBuffer->mFb->mSize;
}

void
EmbedLiteCompositorBridgeParent::CompositeToDefaultTarget(VsyncId aId)
{
  GLContext* context = static_cast<CompositorOGL*>(state->mLayerManager->
      GetCompositor())->gl();
[...]
  if (context->IsOffscreen()) {
    MutexAutoLock lock(mRenderMutex);
    if (context->GetSwapChain()->OffscreenSize() != mEGLSurfaceSize
      && !context->GetSwapChain()->Resize(mEGLSurfaceSize)) {
      return;
    }
  }

(gdb) frame 1
#1  0x0000007ff3667930 in mozilla::embedlite::EmbedLiteCompositorBridgeParent::
    CompositeToDefaultTarget (this=0x7fc4be8da0, aId=...)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:290
290     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/UniquePtr.h:
    No such file or directory.
(gdb) p context
$2 = (mozilla::gl::GLContext *) 0x7ed819ee00
(gdb) p context->GetSwapChain()
Cannot evaluate function -- may be inlined
(gdb) p context.mSwapChain
$3 = {
  mTuple = {<mozilla::detail::CompactPairHelper<mozilla::gl::SwapChain*,
    mozilla::DefaultDelete<mozilla::gl::SwapChain>,
    (mozilla::detail::StorageType)1, (mozilla::detail::StorageType)0>> =
    {<mozilla::DefaultDelete<mozilla::gl::SwapChain>> = {<No data fields>},
    mFirstA = 0x0}, <No data fields>}}
(gdb) p context.mSwapChain.mTuple
$4 = {<mozilla::detail::CompactPairHelper<mozilla::gl::SwapChain*,
    mozilla::DefaultDelete<mozilla::gl::SwapChain>,
    (mozilla::detail::StorageType)1, (mozilla::detail::StorageType)0>> =
    {<mozilla::DefaultDelete<mozilla::gl::SwapChain>> = {<No data fields>},
    mFirstA = 0x0}, <No data fields>}
(gdb) p context.mSwapChain.mTuple.mFirstA
$5 = (mozilla::gl::SwapChain *) 0x0
(gdb) 

(gdb) break CompositorOGL::Initialize
Breakpoint 1 at 0x7ff11b0c3c: file gfx/layers/opengl/CompositorOGL.cpp,
    line 380.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 36 "Compositor" hit Breakpoint 1, mozilla::layers::CompositorOGL::
    Initialize (this=0x7ee0002f50, out_failureReason=0x7f1faac520)
    at gfx/layers/opengl/CompositorOGL.cpp:380
380     bool CompositorOGL::Initialize(nsCString* const out_failureReason) {
(gdb)

bool CompositorOGL::Initialize(nsCString* const out_failureReason) {
  ScopedGfxFeatureReporter reporter("GL Layers");

  // Do not allow double initialization
  MOZ_ASSERT(mGLContext == nullptr || !mOwnsGLContext,
             "Don't reinitialize CompositorOGL");

  if (!mGLContext) {
    MOZ_ASSERT(mOwnsGLContext);
    mGLContext = CreateContext();
  }
[...]

Thread 36 "Compositor" hit Breakpoint 5, mozilla::layers::CompositorOGL::
    CreateContext (this=this@entry=0x7ee0002f50)
    at gfx/layers/opengl/CompositorOGL.cpp:227
227     already_AddRefed<mozilla::gl::GLContext> CompositorOGL::CreateContext() {
(gdb) n
231       nsIWidget* widget = mWidget->RealWidget();
(gdb) 
232       void* widgetOpenGLContext =
(gdb) 
234       if (widgetOpenGLContext) {
(gdb) 
248       if (!context && gfxEnv::LayersPreferOffscreen()) {
(gdb) b GLContextProviderEGL::CreateHeadless
Breakpoint 6 at 0x7ff1133740: file gfx/gl/GLContextProviderEGL.cpp, line 1245.
(gdb) c
Continuing.

Thread 36 "Compositor" hit Breakpoint 6, mozilla::gl::GLContextProviderEGL::
    CreateHeadless (desc=..., out_failureId=out_failureId@entry=0x7f1faed1c8)
    at gfx/gl/GLContextProviderEGL.cpp:1245
1245        const GLContextCreateDesc& desc, nsACString* const out_failureId) {
(gdb) n
1246      const auto display = DefaultEglDisplay(out_failureId);
(gdb) 
1247      if (!display) {
(gdb) p display
$8 = std::shared_ptr<mozilla::gl::EglDisplay> (use count 1, weak count 2)
    = {get() = 0x7ee0004cb0}
(gdb) n
1250      mozilla::gfx::IntSize dummySize = mozilla::gfx::IntSize(16, 16);
(gdb) b GLContextEGL::CreateEGLPBufferOffscreenContext
Breakpoint 7 at 0x7ff11335b8: file gfx/gl/GLContextProviderEGL.cpp, line 1233.
(gdb) c
Continuing.

Thread 36 "Compositor" hit Breakpoint 7, mozilla::gl::GLContextEGL::
    CreateEGLPBufferOffscreenContext (
    display=std::shared_ptr<mozilla::gl::EglDisplay> (use count 2, weak count 2)
    = {...}, desc=..., size=..., 
    out_failureId=out_failureId@entry=0x7f1faed1c8)
    at gfx/gl/GLContextProviderEGL.cpp:1233
1233        const mozilla::gfx::IntSize& size, nsACString* const
    out_failureId) {
(gdb) b GLContextEGL::CreateEGLPBufferOffscreenContextImpl
Breakpoint 8 at 0x7ff1133160: file gfx/gl/GLContextProviderEGL.cpp, line 1185.
(gdb) c
Continuing.

Thread 36 "Compositor" hit Breakpoint 8, mozilla::gl::GLContextEGL::
    CreateEGLPBufferOffscreenContextImpl (
    egl=std::shared_ptr<mozilla::gl::EglDisplay> (use count 3, weak count 2) =
    {...}, desc=..., size=..., useGles=useGles@entry=false, 
    out_failureId=out_failureId@entry=0x7f1faed1c8)
    at gfx/gl/GLContextProviderEGL.cpp:1185
1185        nsACString* const out_failureId) {
(gdb) n
1186      const EGLConfig config = ChooseConfig(*egl, desc, useGles);
(gdb) 
1187      if (config == EGL_NO_CONFIG) {
(gdb) 
1193      if (GLContext::ShouldSpew()) {
(gdb) 
1197      mozilla::gfx::IntSize pbSize(size);
(gdb) 
1307    include/c++/8.3.0/bits/shared_ptr_base.h: No such file or directory.
(gdb) 
1208      if (!surface) {
(gdb) 
1214      auto fullDesc = GLContextDesc{desc};
(gdb) 
1215      fullDesc.isOffscreen = true;
(gdb) 
1217          egl, fullDesc, config, surface, useGles, out_failureId);
(gdb) b GLContextEGL::CreateGLContext
Breakpoint 9 at 0x7ff1132548: file gfx/gl/GLContextProviderEGL.cpp, line 618.
(gdb) c
Continuing.

Thread 36 "Compositor" hit Breakpoint 9, mozilla::gl::GLContextEGL::
    CreateGLContext (egl=std::shared_ptr<mozilla::gl::EglDisplay>
    (use count 4, weak count 2) = {...}, desc=...,
    config=config@entry=0x55558fc450, surface=surface@entry=0x7ee0008f40,
    useGles=useGles@entry=false, out_failureId=out_failureId@entry=0x7f1faed1c8)
    at gfx/gl/GLContextProviderEGL.cpp:618
618         nsACString* const out_failureId) {
(gdb) n
621       std::vector<EGLint> required_attribs;
(gdb) 

void gfxConfigManager::Init() {
[...]
  mFeatureWr = &gfxConfig::GetFeature(Feature::WEBRENDER);
[...]
  mFeatureWrSoftware = &gfxConfig::GetFeature(Feature::WEBRENDER_SOFTWARE);
[...]

(gdb) delete break
Delete all breakpoints? (y or n) y
(gdb) b gfxConfigManager::ConfigureWebRender
Breakpoint 5 at 0x7fb90a8d88: file gfx/config/gfxConfigManager.cpp, line 194.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 7 "GeckoWorkerThre" hit Breakpoint 5, mozilla::gfx::gfxConfigManager::
    ConfigureWebRender (this=this@entry=0x7fa7972598)
    at gfx/config/gfxConfigManager.cpp:194
194     void gfxConfigManager::ConfigureWebRender() {
(gdb) n
206       mFeatureWrCompositor->SetDefaultFromPref("gfx.webrender.compositor",
    true,
(gdb) n
209       if (mWrCompositorForceEnabled) {
(gdb) n
213       ConfigureFromBlocklist(nsIGfxInfo::FEATURE_WEBRENDER_COMPOSITOR,
(gdb) n
219       if (!mHwStretchingSupport && mScaledResolution) {
(gdb) n
225       bool guardedByQualifiedPref = ConfigureWebRenderQualified();
(gdb) n
300     obj-build-mer-qt-xr/dist/include/nsTStringRepr.h: No such file or directory.
(gdb) p *mFeatureWr
$15 = {mDefault = {mMessage = '\000' <repeats 63 times>, mStatus =
    mozilla::gfx::FeatureStatus::Unused}, mUser = {mMessage = '\000'
    <repeats 63 times>, mStatus = mozilla::gfx::FeatureStatus::Unused},
    mEnvironment = {mMessage = '\000' <repeats 63 times>,
    mStatus = mozilla::gfx::FeatureStatus::Unused}, mRuntime = {mMessage =
    '\000' <repeats 63 times>, mStatus = mozilla::gfx::FeatureStatus::Unused}, 
  mFailureId = {<nsTSubstring<char>> = {<mozilla::detail::nsTStringRepr<char>> =
    {mData = 0x7fbc7d4f42 <gNullChar> "", mLength = 0, mDataFlags =
    mozilla::detail::StringDataFlags::TERMINATED, mClassFlags =
    mozilla::detail::StringClassFlags::NULL_TERMINATED}, 
      static kMaxCapacity = 2147483637}, <No data fields>}}
(gdb) p mFeatureWr->GetValue()
$16 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWr->IsEnabled()
$17 = false
(gdb) p mFeatureWr->mDefault.mStatus
$30 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWr->mRuntime.mStatus
$31 = mozilla::gfx::FeatureStatus::Unused
(gdb) n
235       if (mWrEnvForceEnabled) {
(gdb) p mWrEnvForceEnabled
$18 = false
(gdb) n
237       } else if (mWrForceEnabled) {
(gdb) p mWrForceEnabled
$19 = false
(gdb) n
239       } else if (mFeatureWrQualified->IsEnabled()) {
(gdb) p mFeatureWrQualified->IsEnabled()
$20 = false
(gdb) n
253       if (mWrForceDisabled ||
(gdb) p mWrForceDisabled
$21 = false
(gdb) p mWrEnvForceDisabled
$22 = false
(gdb) p mWrQualifiedOverride.isNothing()
Cannot evaluate function -- may be inlined
(gdb) n
261       if (!mFeatureHwCompositing->IsEnabled()) {
(gdb) n
268       if (mSafeMode) {
(gdb) n
276       if (mIsWindows && !mIsWin10OrLater && !mDwmCompositionEnabled) {
(gdb) p mIsWindows
$23 = false
(gdb) p mIsWin10OrLater
$24 = false
(gdb) p mDwmCompositionEnabled
$25 = true
(gdb) n
283           NS_LITERAL_CSTRING("FEATURE_FAILURE_DEFAULT_OFF"));
(gdb) n
285       if (mFeatureD3D11HwAngle && mWrForceAngle) {
(gdb) n
301       if (!mFeatureWr->IsEnabled() && mDisableHwCompositingNoWr) {
(gdb) p mFeatureWr->IsEnabled()
$26 = false
(gdb) p mDisableHwCompositingNoWr
$27 = false
(gdb) n
324           NS_LITERAL_CSTRING("FEATURE_FAILURE_DEFAULT_OFF"));
(gdb) n
326       if (mWrDCompWinEnabled) {
(gdb) n
334       if (!mWrPictureCaching) {
(gdb) n
340       if (!mFeatureWrDComp->IsEnabled() && mWrCompositorDCompRequired) {
(gdb) n
348       if (mWrPartialPresent) {
(gdb) n
gfxPlatform::InitWebRenderConfig (this=<optimized out>)
    at gfx/thebes/gfxPlatform.cpp:2733
2733      if (Preferences::GetBool("gfx.webrender.program-binary-disk", false)) {
(gdb) c
[...]

(gdb) p mFeatureWr->IsEnabled()
$17 = false
(gdb) p mFeatureWr->mDefault.mStatus
$30 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWr->mRuntime.mStatus
$31 = mozilla::gfx::FeatureStatus::Unused

1. mRuntime
2. mUser
3. mEnvironment
4. mStatus
5. mDefault

1. mFeatureWr->mDefault.mStatus is set to anything other than Unused.
2. The mStatus value of one of the other layers is set to something other than Unused and is either Available or ForceEnabled.

(gdb) delete break
Delete all breakpoints? (y or n) y
(gdb) b gfxConfigManager::ConfigureWebRender
Breakpoint 9 at 0x7ff138d708: file gfx/config/gfxConfigManager.cpp, line 215.
(gdb) b gfxConfigManager::ConfigureWebRenderSoftware
Breakpoint 10 at 0x7ff138d41c: file gfx/config/gfxConfigManager.cpp, line 125.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 7 "GeckoWorkerThre" hit Breakpoint 9, mozilla::gfx::gfxConfigManager::
    ConfigureWebRender (this=this@entry=0x7fd7da72f8)
    at gfx/config/gfxConfigManager.cpp:215
215     void gfxConfigManager::ConfigureWebRender() {
(gdb) p mFeatureWr->IsEnabled()
$13 = false
(gdb) p mFeatureWr->mDefault.mStatus
$14 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWr->mRuntime.mStatus
$15 = mozilla::gfx::FeatureStatus::Unused

(gdb) n
230       mFeatureWrCompositor->SetDefaultFromPref("gfx.webrender.compositor",
    true,
(gdb)
233       if (mWrCompositorForceEnabled) {
(gdb)
237       ConfigureFromBlocklist(nsIGfxInfo::FEATURE_WEBRENDER_COMPOSITOR,
(gdb)
243       if (!mHwStretchingSupport.IsFullySupported() && mScaledResolution) {
(gdb)
253       ConfigureWebRenderSoftware();
(gdb) n

Thread 7 "GeckoWorkerThre" hit Breakpoint 10, mozilla::gfx::gfxConfigManager::
    ConfigureWebRenderSoftware (this=this@entry=0x7fd7da72f8)
    at gfx/config/gfxConfigManager.cpp:125
125     void gfxConfigManager::ConfigureWebRenderSoftware() {
(gdb) p mFeatureWrSoftware->IsEnabled()
$16 = false
(gdb) p mFeatureWrSoftware->mDefault.mStatus
$17 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWrSoftware->mDefault.mStatus
$18 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWrSoftware->mRuntime.mStatus
$19 = mozilla::gfx::FeatureStatus::Unused

(gdb) n
128       mFeatureWrSoftware->EnableByDefault();
(gdb) n
134       if (mWrSoftwareForceEnabled) {
(gdb) p mFeatureWrSoftware->IsEnabled()
$20 = true
(gdb) p mFeatureWrSoftware->mDefault.mStatus
$21 = mozilla::gfx::FeatureStatus::Available
(gdb) p mFeatureWrSoftware->mRuntime.mStatus
$22 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWrSoftware->mUser.mStatus
$23 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWrSoftware->mEnvironment.mStatus
$24 = mozilla::gfx::FeatureStatus::Unused
(gdb) p mFeatureWrSoftware->mDefault.mStatus
$25 = mozilla::gfx::FeatureStatus::Available

(gdb) p mWrSoftwareForceEnabled
$33 = false
(gdb) n
136       } else if (mWrForceDisabled || mWrEnvForceDisabled) {
(gdb) p mWrForceDisabled
$26 = false
(gdb) p mWrEnvForceDisabled
$27 = false

(gdb) n
141       } else if (gfxPlatform::DoesFissionForceWebRender()) {
(gdb) n
145       if (!mHasWrSoftwareBlocklist) {
(gdb) p mHasWrSoftwareBlocklist
$28 = false

(gdb) n
mozilla::gfx::gfxConfigManager::ConfigureWebRender
    (this=this@entry=0x7fd7da72f8)
    at gfx/config/gfxConfigManager.cpp:254
254       ConfigureWebRenderQualified();
(gdb) n
256       mFeatureWr->EnableByDefault();
(gdb) n
262       if (mWrSoftwareForceEnabled) {
(gdb) p mFeatureWr->IsEnabled()
$29 = true
(gdb) n

266       } else if (mWrEnvForceEnabled) {
(gdb) 
268       } else if (mWrForceDisabled || mWrEnvForceDisabled) {
(gdb)
275       } else if (mWrForceEnabled) {
(gdb) p mWrForceEnabled
$30 = false
(gdb) n
279       if (!mFeatureWrQualified->IsEnabled()) {
(gdb) p mFeatureWrQualified->IsEnabled()
$31 = false
(gdb) n
282         mFeatureWr->Disable(FeatureStatus::Disabled, "Not qualified",
(gdb) n
287       if (!mFeatureHwCompositing->IsEnabled()) {
(gdb) p mFeatureWr->IsEnabled()
$32 = false

    // No qualified hardware. If we haven't allowed software fallback,
    // then we need to disable WR.

(gdb) n
293       if (mSafeMode) {
(gdb) n
302       if (mXRenderEnabled) {
(gdb) n
312       mFeatureWrAngle->EnableByDefault();
(gdb) n
313       if (mFeatureD3D11HwAngle) {
(gdb) n
335         mFeatureWrAngle->Disable(FeatureStatus::Unavailable,
    "OS not supported",
(gdb) n
339       if (mWrForceAngle && mFeatureWr->IsEnabled() &&
(gdb) n
347       if (!mFeatureWr->IsEnabled() && mDisableHwCompositingNoWr) {
(gdb) n
367       mFeatureWrDComp->EnableByDefault();
(gdb) n
368       if (!mWrDCompWinEnabled) {
(gdb) n
369         mFeatureWrDComp->UserDisable("User disabled via pref",
(gdb) n
373       if (!mIsWin10OrLater) {
(gdb) n
375         mFeatureWrDComp->Disable(FeatureStatus::Unavailable,
(gdb) n
380       if (!mIsNightly) {
(gdb) n
383         nsAutoString adapterVendorID;
(gdb) n
384         mGfxInfo->GetAdapterVendorID(adapterVendorID);
(gdb) n
385         if (adapterVendorID == u"0x10de") {
(gdb) n
383         nsAutoString adapterVendorID;
(gdb) n
396       mFeatureWrDComp->MaybeSetFailed(
(gdb) n
399       mFeatureWrDComp->MaybeSetFailed(mFeatureWrAngle->IsEnabled(),
(gdb) n
403       if (!mFeatureWrDComp->IsEnabled() && mWrCompositorDCompRequired) {
(gdb) n
411       if (mWrPartialPresent) {
(gdb) n
654     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/StaticPrefList_gfx.h:
    No such file or directory.
(gdb) n
433       ConfigureFromBlocklist(nsIGfxInfo::FEATURE_WEBRENDER_SHADER_CACHE,
(gdb) n
435       if (!mFeatureWr->IsEnabled()) {
(gdb) n
436         mFeatureWrShaderCache->ForceDisable(FeatureStatus::Unavailable,
(gdb) n
441       mFeatureWrOptimizedShaders->EnableByDefault();
(gdb) n
442       if (!mWrOptimizedShaders) {
(gdb) n
446       ConfigureFromBlocklist(nsIGfxInfo::FEATURE_WEBRENDER_OPTIMIZED_SHADERS,
(gdb) n
448       if (!mFeatureWr->IsEnabled()) {
(gdb) n
449         mFeatureWrOptimizedShaders->ForceDisable(FeatureStatus::Unavailable,
(gdb) n

void gfxConfigManager::Init() {
[...]
  mWrForceDisabled = StaticPrefs::gfx_webrender_force_disabled_AtStartup();
[...]
  mWrEnvForceDisabled = gfxPlatform::WebRenderEnvvarDisabled();
[...]

ONCE_PREF(
  "gfx.webrender.force-disabled",
   gfx_webrender_force_disabled,
   gfx_webrender_force_disabled_AtStartup,
  bool, false
)

# Also expose a pref to allow users to force-disable WR. This is exposed
# on all channels because WR can be enabled on qualified hardware on all
# channels.
- name: gfx.webrender.force-disabled
  type: bool
  value: false
  mirror: once

/*static*/
bool gfxPlatform::WebRenderEnvvarDisabled() {
  const char* env = PR_GetEnv("MOZ_WEBRENDER");
  return (env && *env == '0');
}

void DeclarativeWebUtils::setRenderingPreferences()
{
    SailfishOS::WebEngineSettings *webEngineSettings =
        SailfishOS::WebEngineSettings::instance();

    // Use external Qt window for rendering content
    webEngineSettings->setPreference(
        QString("gfx.compositor.external-window"), QVariant(true));
    webEngineSettings->setPreference(
        QString("gfx.compositor.clear-context"), QVariant(false));
    webEngineSettings->setPreference(
        QString("gfx.webrender.force-disabled"), QVariant(true));
    webEngineSettings->setPreference(
        QString("embedlite.compositor.external_gl_context"), QVariant(true));
}

diff --git a/lib/webenginesettings.cpp b/lib/webenginesettings.cpp
index de9e4b86..13b21d5b 100644
--- a/lib/webenginesettings.cpp
+++ b/lib/webenginesettings.cpp
@@ -110,6 +110,10 @@ void SailfishOS::WebEngineSettings::initialize()
     engineSettings->setPreference(QStringLiteral("intl.accept_languages"),
                                   QVariant::fromValue<QString>(langs));
 
+    // Ensure the web renderer is disabled
+    engineSettings->setPreference(QStringLiteral("gfx.webrender.force-disabled"),
+                                  QVariant(true));
+
     Silica::Theme *silicaTheme = Silica::Theme::instance();
 
     // Notify gecko when the ambience switches between light and dark

diff --git a/import/webview/rawwebview.cpp b/import/webview/rawwebview.cpp
index 1b1bb92a..2eab77f5 100644
--- a/import/webview/rawwebview.cpp
+++ b/import/webview/rawwebview.cpp
@@ -37,7 +37,7 @@ public:
     ViewCreator();
     ~ViewCreator();
 
-    quint32 createView(const quint32 &parentId, const uintptr_t &parentBrowsingContext) override;
+    quint32 createView(const quint32 &parentId, const uintptr_t &parentBrowsingContext, bool hidden) override;
 
     static std::shared_ptr<ViewCreator> instance();
 
@@ -54,9 +54,10 @@ ViewCreator::~ViewCreator()
     SailfishOS::WebEngine::instance()->setViewCreator(nullptr);
 }
 
-quint32 ViewCreator::createView(const quint32 &parentId, const uintptr_t &parentBrowsingContext)
+quint32 ViewCreator::createView(const quint32 &parentId, const uintptr_t &parentBrowsingContext, bool hidden)
 {
     Q_UNUSED(parentBrowsingContext)
+    Q_UNUSED(hidden)
 
     for (RawWebView *view : views) {
         if (view->uniqueId() == parentId) {

[defaultuser@Xperia10III gecko]$ harbour-webview 
[D] unknown:0 - QML debugging is enabled. Only use this in a safe environment.
[D] main:30 - WebView Example
[D] main:44 - Using default start URL:  "https://www.flypig.co.uk/search/"
[D] main:47 - Opening webview
[D] unknown:0 - Using Wayland-EGL
library "libutils.so" not found
library "libcutils.so" not found
library "libhardware.so" not found
library "android.hardware.graphics.mapper@2.0.so" not found
library "android.hardware.graphics.mapper@2.1.so" not found
library "android.hardware.graphics.mapper@3.0.so" not found
library "android.hardware.graphics.mapper@4.0.so" not found
library "libc++.so" not found
library "libhidlbase.so" not found
library "libgralloctypes.so" not found
library "android.hardware.graphics.common@1.2.so" not found
library "libion.so" not found
library "libz.so" not found
library "libhidlmemory.so" not found
library "android.hidl.memory@1.0.so" not found
library "vendor.qti.qspmhal@1.0.so" not found
greHome from GRE_HOME:/usr/bin
libxul.so is not found, in /usr/bin/libxul.so
Created LOG for EmbedLiteTrace
[W] unknown:7 - file:///usr/share/harbour-webview/qml/harbour-webview.qml:7:30:
    Type WebViewPage unavailable 
         initialPage: Component { WebViewPage { } } 
                                  ^
[W] unknown:13 - file:///usr/share/harbour-webview/qml/pages/
    WebViewPage.qml:13:5: Type WebView unavailable 
         WebView { 
         ^
[W] unknown:141 - file:///usr/lib64/qt5/qml/Sailfish/WebView/WebView.qml:141:9:
    Type TextSelectionController unavailable 
             TextSelectionController { 
             ^
[W] unknown:14 - file:///usr/lib64/qt5/qml/Sailfish/WebView/Controls/
    TextSelectionController.qml:14:1: module "QOfono" is not installed 
     import QOfono 0.2 
     ^
Created LOG for EmbedLite
JSComp: EmbedLiteConsoleListener.js loaded
JSComp: ContentPermissionManager.js loaded
JSComp: EmbedLiteChromeManager.js loaded
JSComp: EmbedLiteErrorPageHandler.js loaded
JSComp: EmbedLiteFaviconService.js loaded
JSComp: EmbedLiteGlobalHelper.js loaded
EmbedLiteGlobalHelper app-startup
JSComp: EmbedLiteOrientationChangeHandler.js loaded
JSComp: EmbedLiteSearchEngine.js loaded
JSComp: EmbedLiteSyncService.js loaded
EmbedLiteSyncService app-startup
JSComp: EmbedLiteWebrtcUI.js: loaded
JSComp: EmbedLiteWebrtcUI.js: got app-startup
JSComp: EmbedPrefService.js loaded
EmbedPrefService app-startup
JSComp: EmbedliteDownloadManager.js loaded
JSComp: LoginsHelper.js loaded
JSComp: PrivateDataManager.js loaded
JSComp: UserAgentOverrideHelper.js loaded
UserAgentOverrideHelper app-startup
CONSOLE message:
[JavaScript Error: "Unexpected event profile-after-change" {file:
    "resource://gre/modules/URLQueryStrippingListService.jsm" line: 228}]
observe@resource://gre/modules/URLQueryStrippingListService.jsm:228:12

Created LOG for EmbedPrefs

$ gdb harbour-webview
[...]
(gdb) b nsBaseWidget::CreateCompositorSession
Function "nsBaseWidget::CreateCompositorSession" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (nsBaseWidget::CreateCompositorSession) pending.
(gdb) r
[...]
Thread 7 "GeckoWorkerThre" hit Breakpoint 1, nsBaseWidget::
    CreateCompositorSession (this=this@entry=0x7f8ccbf3d0, aWidth=1080,
    aHeight=2520, aOptionsOut=aOptionsOut@entry=0x7fa7972ac0)
    at widget/nsBaseWidget.cpp:1176
1176        int aWidth, int aHeight, CompositorOptions* aOptionsOut) {
(gdb) n
1180        CreateCompositorVsyncDispatcher();
(gdb) n
1182        gfx::GPUProcessManager* gpu = gfx::GPUProcessManager::Get();
(gdb) n
1186        gpu->EnsureGPUReady();
(gdb) n
67      obj-build-mer-qt-xr/dist/include/mozilla/StaticPtr.h:
    No such file or directory.
(gdb) n
1193        bool enableAPZ = UseAPZ();
(gdb) n
1194        CompositorOptions options(enableAPZ, enableWR);
(gdb) n
1198        bool enableAL =
(gdb) n
1203        options.SetUseWebGPU(StaticPrefs::dom_webgpu_enabled());
(gdb) n
50      obj-build-mer-qt-xr/dist/include/mozilla/layers/CompositorOptions.h:
    No such file or directory.
(gdb) n
1210        options.SetInitiallyPaused(CompositorInitiallyPaused());
(gdb) n
53      obj-build-mer-qt-xr/dist/include/mozilla/layers/CompositorOptions.h:
    No such file or directory.
(gdb) 
39      in obj-build-mer-qt-xr/dist/include/mozilla/layers/CompositorOptions.h
(gdb) 
1217          lm = new ClientLayerManager(this);
(gdb) p enableWR
$1 = false
(gdb) p enableAPZ
$2 = <optimized out>
(gdb) p enableAL
$3 = <optimized out>
(gdb) p gfx::gfxConfig::IsEnabled(gfx::Feature::ADVANCED_LAYERS)
$4 = false
(gdb) p mFissionWindow
$5 = false
(gdb) p StaticPrefs::layers_advanced_fission_enabled()
No symbol "layers_advanced_fission_enabled" in namespace "mozilla::StaticPrefs".
(gdb) p StaticPrefs::dom_webgpu_enabled()
$6 = false
(gdb) p options.UseWebRender()
Cannot evaluate function -- may be inlined
(gdb) p options
$7 = {mUseAPZ = true, mUseWebRender = false, mUseAdvancedLayers = false,
    mUseWebGPU = false, mInitiallyPaused = false}
(gdb) 

  CompositorOptions(bool aUseAPZ, bool aUseWebRender,
                    bool aUseSoftwareWebRender)
      : mUseAPZ(aUseAPZ),
        mUseWebRender(aUseWebRender),
        mUseSoftwareWebRender(aUseSoftwareWebRender) {
    MOZ_ASSERT_IF(aUseSoftwareWebRender, aUseWebRender);
  }

    bool enableWR =
        gfx::gfxVars::UseWebRender() && WidgetTypeSupportsAcceleration();

(gdb) p WidgetTypeSupportsAcceleration()
$8 = true
(gdb) p gfx::gfxVars::UseWebRender()
Cannot evaluate function -- may be inlined

(gdb) p gfx::gfxVars::sInstance.mRawPtr.mVarUseWebRender.mValue
$11 = false

$ grep -rIn "gfxVars::SetUseWebRender(" * --include="*.cpp"
gecko-dev/gfx/thebes/gfxPlatform.cpp:2750:    gfxVars::SetUseWebRender(true);
gecko-dev/gfx/thebes/gfxPlatform.cpp:3297:    gfxVars::SetUseWebRender(false);
gecko-dev/gfx/ipc/GPUProcessManager.cpp:479:  gfx::gfxVars::SetUseWebRender(false);

(gdb) delete break
Delete all breakpoints? (y or n) y
(gdb) break gfxPlatform::InitWebRenderConfig
Breakpoint 2 at 0x7fb9013328: file gfx/thebes/gfxPlatform.cpp, line 2691.
(gdb) b gfxPlatform::NotifyGPUProcessDisabled
Breakpoint 3 at 0x7fb9016fb0: file gfx/thebes/gfxPlatform.cpp, line 3291.
(gdb) b GPUProcessManager::DisableWebRender
Breakpoint 4 at 0x7fb907f858: GPUProcessManager::DisableWebRender. (3 locations)
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 7 "GeckoWorkerThre" hit Breakpoint 2, gfxPlatform::InitWebRenderConfig
    (this=0x7f8c8bbf60)
    at gfx/thebes/gfxPlatform.cpp:2691
2691    void gfxPlatform::InitWebRenderConfig() {
(gdb) n
2692      bool prefEnabled = WebRenderPrefEnabled();
(gdb) n
2693      bool envvarEnabled = WebRenderEnvvarEnabled();
(gdb) n
2698      gfxVars::AddReceiver(&nsCSSProps::GfxVarReceiver());
(gdb) n
2708      ScopedGfxFeatureReporter reporter("WR", prefEnabled || envvarEnabled);
(gdb) n
2709      if (!XRE_IsParentProcess()) {
(gdb) n
2723      gfxConfigManager manager;
(gdb) n
2725      manager.ConfigureWebRender();
(gdb) n
2733      if (Preferences::GetBool("gfx.webrender.program-binary-disk", false)) {
(gdb) n
2738      if (StaticPrefs::gfx_webrender_use_optimized_shaders_AtStartup()) {
(gdb) n
2739        gfxVars::SetUseWebRenderOptimizedShaders(
(gdb) n
2743      if (Preferences::GetBool("gfx.webrender.software", false)) {
(gdb) p gfxConfig::IsEnabled(Feature::WEBRENDER)
$12 = false
(gdb) n
2749      if (gfxConfig::IsEnabled(Feature::WEBRENDER)) {
(gdb) n
2791      if (gfxConfig::IsEnabled(Feature::WEBRENDER_COMPOSITOR)) {
(gdb) p gfxConfig::IsEnabled(Feature::WEBRENDER_COMPOSITOR)
$13 = false
(gdb) n
2795      Telemetry::ScalarSet(
(gdb) n
2799      if (gfxConfig::IsEnabled(Feature::WEBRENDER_PARTIAL)) {
(gdb) n
2805      gfxVars::SetUseGLSwizzle(
(gdb) n
2810      gfxUtils::RemoveShaderCacheFromDiskIfNecessary();
(gdb) r
[...]

    bool supportsAcceleration = WidgetTypeSupportsAcceleration();
    bool enableWR;
    if (supportsAcceleration ||
        StaticPrefs::gfx_webrender_unaccelerated_widget_force()) {
      enableWR = gfx::gfxVars::UseWebRender();
    } else if (gfxPlatform::DoesFissionForceWebRender() ||
               StaticPrefs::
                   gfx_webrender_software_unaccelerated_widget_allow()) {
      enableWR = gfx::gfxVars::UseWebRender();
    } else {
      enableWR = false;
    }

      enableWR = gfx::gfxVars::UseWebRender();

$ grep -rIn "gfxVars::SetUseWebRender(" * --include="*.cpp"
gecko-dev/gfx/thebes/gfxPlatform.cpp:2713:    gfxVars::SetUseWebRender(true);
gecko-dev/gfx/thebes/gfxPlatform.cpp:3435:      gfxVars::SetUseWebRender(true);
gecko-dev/gfx/thebes/gfxPlatform.cpp:3475:    gfxVars::SetUseWebRender(false);

(gdb) delete break
Delete all breakpoints? (y or n) y
(gdb) b gfxPlatform::InitWebRenderConfig
Breakpoint 7 at 0x7ff12ef954: file gfx/thebes/gfxPlatform.cpp, line 2646.
(gdb) b gfxPlatform::FallbackFromAcceleration
Breakpoint 8 at 0x7ff12f3048: file gfx/thebes/gfxPlatform.cpp, line 3381.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Thread 7 "GeckoWorkerThre" hit Breakpoint 7, gfxPlatform::InitWebRenderConfig
    (this=0x7fc4a48c90)
    at gfx/thebes/gfxPlatform.cpp:2646
2646    void gfxPlatform::InitWebRenderConfig() {
(gdb) n
2647      bool prefEnabled = WebRenderPrefEnabled();
(gdb) n
2648      bool envvarEnabled = WebRenderEnvvarEnabled();
(gdb)
[New LWP 27297]
2653      gfxVars::AddReceiver(&nsCSSProps::GfxVarReceiver());
(gdb) 
2663      ScopedGfxFeatureReporter reporter("WR", prefEnabled || envvarEnabled);
(gdb) 
32      ${PROJECT}/obj-build-mer-qt-xr/dist/include/gfxCrashReporterUtils.h:
    No such file or directory.
(gdb) 
2664      if (!XRE_IsParentProcess()) {
(gdb) 
2678      gfxConfigManager manager;
(gdb) 
2679      manager.Init();
(gdb) 
2680      manager.ConfigureWebRender();
(gdb) 
2682      bool hasHardware = gfxConfig::IsEnabled(Feature::WEBRENDER);
(gdb) 
2683      bool hasSoftware = gfxConfig::IsEnabled(Feature::WEBRENDER_SOFTWARE);
(gdb) 
2684      bool hasWebRender = hasHardware || hasSoftware;
(gdb) p hasHardware
$10 = false
(gdb) p hasSoftware
$11 = true
(gdb) p hasWebRender
$12 = <optimized out>
(gdb) n
2701      if (gfxConfig::IsEnabled(Feature::WEBRENDER_SHADER_CACHE)) {
(gdb) n
2705      gfxVars::SetUseWebRenderOptimizedShaders(
(gdb) n
2708      gfxVars::SetUseSoftwareWebRender(!hasHardware && hasSoftware);
(gdb) n
2712      if (hasWebRender) {
(gdb) n
2713        gfxVars::SetUseWebRender(true);
(gdb) c
[...]

bool PuppetWidget::CreateRemoteLayerManager(
    const std::function<bool(LayerManager*)>& aInitializeFunc) {
  RefPtr<LayerManager> lm;
  MOZ_ASSERT(mBrowserChild);
  if (mBrowserChild->GetCompositorOptions().UseWebRender()) {
    lm = new WebRenderLayerManager(this);
  } else {
    lm = new ClientLayerManager(this);
  }
[...]

already_AddRefed<LayerManager> nsBaseWidget::CreateCompositorSession(
    int aWidth, int aHeight, CompositorOptions* aOptionsOut) {
[...]
    gfx::GPUProcessManager* gpu = gfx::GPUProcessManager::Get();
    // Make sure GPU process is ready for use.
    // If it failed to connect to GPU process, GPU process usage is disabled in
    // EnsureGPUReady(). It could update gfxVars and gfxConfigs.
    gpu->EnsureGPUReady();

    // If widget type does not supports acceleration, we may be allowed to use
    // software WebRender instead. If not, then we use ClientLayerManager even
    // when gfxVars::UseWebRender() is true. WebRender could coexist only with
    // BasicCompositor.
[...]
    RefPtr<LayerManager> lm;
    if (options.UseWebRender()) {
      lm = new WebRenderLayerManager(this);
    } else {
      lm = new ClientLayerManager(this);
    }
[...]

(gdb) break nsBaseWidget.cpp:1364
Breakpoint 3 at 0x7ff2a57b64: file widget/nsBaseWidget.cpp, line 1364.
(gdb) break PuppetWidget.cpp:616
Breakpoint 4 at 0x7ff2a67d48: file widget/PuppetWidget.cpp, line 616.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]
Created LOG for EmbedLiteLayerManager

Thread 7 "GeckoWorkerThre" hit Breakpoint 3, nsBaseWidget::
    CreateCompositorSession (this=this@entry=0x7fc4dad520,
    aWidth=aWidth@entry=1080, aHeight=aHeight@entry=2520,
    aOptionsOut=aOptionsOut@entry=0x7fd7da7770)
    at widget/nsBaseWidget.cpp:1364
1364        options.SetInitiallyPaused(CompositorInitiallyPaused());
(gdb) n
43      ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/
    CompositorOptions.h: No such file or directory.
(gdb) 
1369          lm = new WebRenderLayerManager(this);
(gdb) p options
$4 = {mUseAPZ = true, mUseWebRender = true, mUseSoftwareWebRender = true,
    mAllowSoftwareWebRenderD3D11 = false, mAllowSoftwareWebRenderOGL = false, 
  mUseAdvancedLayers = false, mUseWebGPU = false, mInitiallyPaused = false}
(gdb) 

(gdb) delete break
Delete all breakpoints? (y or n) y
(gdb) break nsBaseWidget::CreateCompositorSession
Breakpoint 5 at 0x7ff2a578f8: file widget/nsBaseWidget.cpp, line 1308.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/harbour-webview 
[...]

Thread 7 "GeckoWorkerThre" hit Breakpoint 5, nsBaseWidget::
    CreateCompositorSession (this=this@entry=0x7fc4db8a30,
    aWidth=aWidth@entry=1080, aHeight=aHeight@entry=2520,
    aOptionsOut=aOptionsOut@entry=0x7fd7da7770)
    at widget/nsBaseWidget.cpp:1308
1308        int aWidth, int aHeight, CompositorOptions* aOptionsOut) {
(gdb) n
1312        CreateCompositorVsyncDispatcher();
(gdb) n
1314        gfx::GPUProcessManager* gpu = gfx::GPUProcessManager::Get();
(gdb) n
1318        gpu->EnsureGPUReady();
(gdb) n
1324        bool supportsAcceleration = WidgetTypeSupportsAcceleration();
(gdb) n
1327        if (supportsAcceleration ||
(gdb) n
1329          enableWR = gfx::gfxVars::UseWebRender();
(gdb) n
195     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/gfx/gfxVars.h:
    No such file or directory.
(gdb) n
1338        bool enableAPZ = UseAPZ();
(gdb) n
1339        CompositorOptions options(enableAPZ, enableWR, enableSWWR);
(gdb) p supportsAcceleration
$8 = <optimized out>
(gdb) p enableAPZ
$5 = true
(gdb) p enableWR
$6 = true
(gdb) p enableSWWR
$7 = true
(gdb) n
1357        options.SetUseWebGPU(StaticPrefs::dom_webgpu_enabled());
(gdb) p StaticPrefs::dom_webgpu_enabled()
$9 = false
(gdb) n
mozilla::Atomic<bool, (mozilla::MemoryOrdering)0, void>::operator bool
    (this=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/
    CompositorOptions.h:67
67      ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/
    CompositorOptions.h: No such file or directory.
(gdb) n
nsBaseWidget::CreateCompositorSession (this=this@entry=0x7fc4db8a30,
    aWidth=aWidth@entry=1080, aHeight=aHeight@entry=2520, 
    aOptionsOut=aOptionsOut@entry=0x7fd7da7770)
    at widget/nsBaseWidget.cpp:1364
1364        options.SetInitiallyPaused(CompositorInitiallyPaused());
(gdb) n
43      ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/layers/
    CompositorOptions.h: No such file or directory.
(gdb) n
1369          lm = new WebRenderLayerManager(this);
(gdb) 

#0  PuppetWidgetBase::Invalidate (this=0x7fc4dac130, aRect=...)
    at mobile/sailfishos/embedshared/PuppetWidgetBase.cpp:274
#1  PuppetWidgetBase::UpdateBounds (...)
    at mobile/sailfishos/embedshared/PuppetWidgetBase.cpp:395
#2  EmbedLiteWindowChild::CreateWidget (this=0x7fc4d626d0)
    at xpcom/base/nsCOMPtr.h:851
#3  RunnableMethodArguments<>::applyImpl...
    at obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1151
[...]
#28 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6

void
PuppetWidgetBase::Invalidate(const LayoutDeviceIntRect &aRect)
{
[...]

  if (mozilla::layers::LayersBackend::LAYERS_CLIENT == lm->GetBackendType()) {
    // No need to do anything, the compositor will handle drawing
  } else {
    MOZ_CRASH("Unexpected layer manager type");
  }
[...]

  virtual mozilla::layers::LayersBackend GetBackendType() override {
    return LayersBackend::LAYERS_OPENGL; }

  LOGW("WEBVIEW: Invalidate LAYERS_CLIENT: %d", lm->GetBackendType());
  if (mozilla::layers::LayersBackend::LAYERS_CLIENT == lm->GetBackendType()) {
    // No need to do anything, the compositor will handle drawing
  } else {
    MOZ_CRASH("Unexpected layer manager type");
  }

enum class LayersBackend : int8_t {
  LAYERS_NONE = 0,
  LAYERS_BASIC,
  LAYERS_OPENGL,
  LAYERS_D3D11,
  LAYERS_CLIENT,
  LAYERS_WR,
  LAYERS_LAST
};

(gdb) p lm->GetBackendType()
$2 = mozilla::layers::LayersBackend::LAYERS_WR
(gdb) ptype lm
type = class mozilla::layers::LayerManager : public mozilla::layers::FrameRecorder {
  protected:
    nsAutoRefCnt mRefCnt;
[...]
    virtual mozilla::layers::LayersBackend GetBackendType(void);
[...]
  protected:
    ~LayerManager();
[...]
} *
(gdb) p this->GetLayerManager(0, mozilla::layers::LayersBackend::LAYERS_NONE, LAYER_MANAGER_CURRENT)
$2 = (mozilla::layers::LayerManager *) 0x7fc4db1250

(gdb) set print object on
(gdb) p this->GetLayerManager(0, mozilla::layers::LayersBackend::LAYERS_NONE, LAYER_MANAGER_CURRENT)
$3 = (mozilla::layers::WebRenderLayerManager *) 0x7fc4db1250
(gdb) set print object off

  LayersBackend GetBackendType() override { return LayersBackend::LAYERS_WR; }

import QtQuick 2.0
import Sailfish.Silica 1.0
import Sailfish.WebView 1.0
import Sailfish.WebEngine 1.0
import uk.co.flypig.webview 1.0

Page {
    allowedOrientations: Orientation.All

    WebView {
        anchors.fill: parent
        active: true
        url: "http://www.sailfishos.org"
        onLinkClicked: {
          WebEngine.notifyObservers("exampleTopic", url)
        }
    }
}

$ harbour-webview
[D] unknown:0 - QML debugging is enabled. Only use this in a safe environment.
[...]
JSComp: UserAgentOverrideHelper.js loaded
UserAgentOverrideHelper app-startup
CONSOLE message:
[JavaScript Error: "Unexpected event profile-after-change"
    {file: "resource://gre/modules/URLQueryStrippingListService.jsm" line: 228}]
observe@resource://gre/modules/URLQueryStrippingListService.jsm:228:12

Created LOG for EmbedPrefs
Content JS: resource://gre/modules/SearchSettings.jsm, function: get, message:
    [JavaScript Warning: "get: No settings file exists, new profile?
    NotFoundError: Could not open the file at
    .cache/harbour-webview/harbour-webview/.mozilla/search.json.mozlz4"]
Created LOG for EmbedLiteLayerManager
Segmentation fault

$ gdb harbour-webview 
GNU gdb (GDB) Mer (8.2.1+git9)
Copyright (C) 2018 Free Software Foundation, Inc.
[...]
Thread 7 "GeckoWorkerThre" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 12581]
0x0000007ff367c0a8 in mozilla::embedlite::PuppetWidgetBase::Invalidate
    (this=0x7fc4dac130, aRect=...)
    at mobile/sailfishos/embedshared/PuppetWidgetBase.cpp:274
274         MOZ_CRASH("Unexpected layer manager type");
(gdb) bt
#0  0x0000007ff367c0a8 in mozilla::embedlite::PuppetWidgetBase::Invalidate
    (this=0x7fc4dac130, aRect=...)
    at mobile/sailfishos/embedshared/PuppetWidgetBase.cpp:274
#1  0x0000007ff368093c in mozilla::embedlite::PuppetWidgetBase::UpdateBounds
    (this=0x7fc4dac130, aRepaint=aRepaint@entry=true)
    at mobile/sailfishos/embedshared/PuppetWidgetBase.cpp:395
#2  0x0000007ff3689b28 in mozilla::embedlite::EmbedLiteWindowChild::CreateWidget
    (this=0x7fc4d626d0)
    at xpcom/base/nsCOMPtr.h:851
#3  0x0000007ff367a094 in mozilla::detail::RunnableMethodArguments<>::applyImpl
    <mozilla::embedlite::EmbedLiteWindowChild, void
    (mozilla::embedlite::EmbedLiteWindowChild::*)()>
    (mozilla::embedlite::EmbedLiteWindowChild*, void
    (mozilla::embedlite::EmbedLiteWindowChild::*)(), mozilla::Tuple<>&,
    std::integer_sequence<unsigned long>) (args=..., m=<optimized out>,
    o=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1151
[...]
#28 0x0000007ff6a0489c in ?? () from /lib64/libc.so.6
(gdb) 

1. Collect the names and avatars.
2. Process the avatars.
3. Plot the names and avatars on the canvas.
4. Tidy things up.

000exploit, 000exploit.png
aerique, aerique.png
Adrian McEwen, amcewen.png
ApB, apb.png
Adam T, atib.png
[...]

ImageMagick suite. It performs a vast array of image manipulations all from the command line. Here's just the a small flavour from its help output:

$ convert --help
Version: ImageMagick 6.9.11-60 Q16 x86_64 2021-01-25 https://imagemagick.org
Copyright: (C) 1999-2021 ImageMagick Studio LLC
License: https://imagemagick.org/script/license.php
Features: Cipher DPC Modules OpenMP(4.5) 
Delegates (built-in): bzlib djvu fftw fontconfig freetype heic jbig jng jp2
    jpeg lcms lqr ltdl lzma openexr pangocairo png tiff webp wmf x xml zlib
Usage: convert-im6.q16 [options ...] file [ [options ...] file ...]
    [options ...] file

Image Settings:
  -adjoin              join images into a single multi-image file
  -affine matrix       affine transform matrix
  -alpha option        activate, deactivate, reset, or set the alpha channel
  -antialias           remove pixel-aliasing
  -authenticate password
                       decipher image with this password
  -attenuate value     lessen (or intensify) when adding noise to an image
[...]

Happily for me, all three of my desired conversions (changing format, changing size, applying a mask) were available using the tool. I put together a very simple bash script which cycles through all of the files with a given format in a folder, processes them in the way that was needed and then output them to a different folder with a suffix added to the filename.

All of the work is done by the convert tool, via this simple addmask.sh script. It's so simple in fact that I can give the entirety of it here without it taking up too much space:

SUFFIX_FROM=$1
OUT_FOLDER=$2
SUFFIX_TO=$3

set -e

if [ $# -ne 3 ]; then
        echo "Syntax: " $0 "<extension-in> <out-folder> <out-suffix>"
        exit 0
fi

SUFFIX_FROM_DOT="${SUFFIX_FROM}."

echo "Converting <image>.$SUFFIX_FROM images to <image>-$SUFFIX_TO.png"
echo

for name in *.$SUFFIX_FROM; do
	newname="${name%.*}$SUFFIX_TO.png"
        echo "Converting $name to $OUT_FOLDER/$newname"
	convert "$name" masks/mask.png -sample 240x240 -alpha Off -compose \
	    CopyOpacity -composite -density 180 -background transparent \
	    "$OUT_FOLDER/$newname"
done

I then called it a couple of times inside the folder with the images to produce the results needed:

$ ./addmask.sh png masked -masked
$ ./addmask.sh jpg masked -masked

After processing, each of the updated images is given a new name, so I had to perform a regex search and replace on my CSV file to update them appropriately. The file now looks like this:

000exploit, 000exploit-masked.png
aerique, aerique-masked.png
Adrian McEwen, amcewen-masked.png
ApB, apb-masked.png
Adam T, atib-masked.png
[...]

I have to admit that I cheated a bit with this script. I originally wrote it back in September 2022 for Jolla's "Sailing for Ten Years" party held in Berlin on 14th October of the same year. Nico Cartron wrote up a nice summary of the event in the Sailfish Community News at the time. I was asked to give a presentation at the event; one of the slides I created for it was a thank you slide not unlike the one above. In that case it was for translators and apps, but it never actually got used during the event.

Nevertheless the script lived on in my file system and finally found itself a use. To be honest, I was pretty tight for time writing up my presentation for FOSDEM so I'm not sure if I'd have gone down this route if I didn't already have something to build on. I made some small changes to it to handle resizing, but that was pretty much the only change.

That brings us to step three. Now having a directory full of nicely processed images, I needed them to be arranged on a canvas, ideally in SVG format, so that I could then embed the result on a slide.

Since starting my role as a Research Data Scientist I've been immersed in random Python scripts. Python has the benefit of a huge array of random libraries to draw from, SVG-writing included in the form of the drawsvg 2 project. It is, honestly, a really simple way to generate SVGs quickly and easily. Now that I've tried it I think I'll be using it more often.

My aim was to arrange the avatars and names "randomly" on the page. I started by creating a method that placed a single avatar on the canvas with the username underneath. Getting the scale, font and formatting correct took a little trial and error, but I was happy that the final values all made sense. The drawsvg coordinate system works just as it should!

Arranging them at random requires an algorithm. My first instinct was to arrange them all in a grid, but with a random "jitter" applied. That is, for each image select a random angle and distance and move it by that amount on the page.

The script I created for this is a little too long to show here, but you can check it out on GitHub.

Here's how I ran it:

$ python3 createthanks.py names.csv thanks-grid.svg --grid
Using grid formation
Exported to thanks-grid.svg

The results weren't good, as you can see for yourself in this image.


 

The avatars have been placed, but the grid formation is still very clear despite the added jitter, plus there's a gap at the end because the number of avatars in total doesn't divide by the number of avatars on each row. I wasn't happy with it.

So I came up with an alternative solution: for each avatar a random location is chosen on the canvas. As each avatar is added its position is stored in an array, then when the next position is chosen it's compared against all of these positions. If it's within a certain distance (60 units) of any of the other points, it's rejected and a new random position is chosen.

Again, you can see this algorithm given in the same file on GitHub. Here's how I ran it:

$ python3 createthanks.py names.csv thanks-random.svg
Using random formation
100%
Exported to thanks-random.svg

This is the approach I ended up using, so you can see the results in the original slide. But it's not ideal for several reasons. Most crucially it's not guaranteed to complete, for example if there isn't enough space to fit all of the avatars the algorithm will hang indefinitely while it tries to find a place to position the next avatar. It's also inefficient, with each location being compared with every other and a potentially large number of rejections being made before a suitable location is found at each step.

But I found given enough space to locate the avatars the process actually finished pretty quickly. And since I only need to run it once, not multiple times, that's actually not a problem.

In retrospect a better algorithm would have been to partition the canvas up into a grid of sizes much smaller than an avatar. Ideally it would be one pixel per pixel, but in practice we don't really know what a pixel means in this context. Besides which something approaching this is likely to be fine. Now store a Boolean associated with each of these grid points indicating whether it's available or used.

After placing an avatar mark the pixels around the location in this grid as being used, to the extent that there will be no overlap if another avatar is placed in any of the unused spots. Keep a count of the available locations.

Then a random number can be chosen between zero and the total remaining available locations in order to select the next spot.

I didn't implement this, but in my head it works really well.

Finally step four involved tidying up the files. Some of the avatars and usernames were overlapping so needed a bit of manual tweaking (but thankfully not too much). Plus I also had to manually make room for the "Thank you" text in the top left of the window. This required a bit more manual shuffling of avatars, but it all worked out in the end. I'm quite happy with how it came out.

That's it. Just a little diversion into the scripts used to create the image; I hope it's been of some interest.

There will be more of the usual gecko dev diary tomorrow.

If you'd like to read any of my other gecko diary entries, they're all available on my Gecko-dev Diary page.

1. When launched from the app grid the sandbox is used. It's not used when launched from the command line.
2. When launched from the app grid the booster is used, unlike when launched from the command line.

$ devel-su journalctl --system -f
[...]
booster-browser[14470]: [D] unknown:0 - Using Wayland-EGL
autologind[5343]: library "libutils.so" not found
autologind[5343]: library "libcutils.so" not found
autologind[5343]: library "libhardware.so" not found
autologind[5343]: library "android.hardware.graphics.mapper@2.0.so" not found
autologind[5343]: library "android.hardware.graphics.mapper@2.1.so" not found
autologind[5343]: library "android.hardware.graphics.mapper@3.0.so" not found
autologind[5343]: library "android.hardware.graphics.mapper@4.0.so" not found
autologind[5343]: library "libc++.so" not found
autologind[5343]: library "libhidlbase.so" not found
autologind[5343]: library "libgralloctypes.so" not found
autologind[5343]: library "android.hardware.graphics.common@1.2.so" not found
autologind[5343]: library "libion.so" not found
autologind[5343]: library "libz.so" not found
autologind[5343]: library "libhidlmemory.so" not found
autologind[5343]: library "android.hidl.memory@1.0.so" not found
autologind[5343]: library "vendor.qti.qspmhal@1.0.so" not found
[...]

vim /usr/lib64/mozembedlite/chrome/embedlite/content/Logger.js

[...]
  get stackTraceEnabled() {
    return true;
    //return this._consoleEnv.indexOf("stacktrace") !== -1;
  },

  get devModeNetworkEnabled() {
    return true;
    //return this._consoleEnv.indexOf("network") !== -1;
  }, 
[...]

$ devel-su journalctl --system -f | grep "dbus-daemon" > sailjail-log-01.txt

$ ls -lh sailjail-log-01.txt 
-rw-rw-r--    1 defaultu defaultu   80.0K Feb 13 22:35 sailjail-log-01.txt

[ Request details ------------------------------------------- ]
    Request: GET status: 200 OK
    URL: https://duckduckgo.com/?t=h_
    [ Request headers --------------------------------------- ]
        Host : duckduckgo.com
        User-Agent : Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101
            Firefox/91.0
        Accept : text/html,application/xhtml+xml,application/xml;q=0.9,
            image/webp,*/*;q=0.8
        Accept-Language : en-GB,en;q=0.5
        Accept-Encoding : gzip, deflate, br
        Connection : keep-alive
        Cookie : l=wt-wt
        Upgrade-Insecure-Requests : 1
        Sec-Fetch-Dest : document
        Sec-Fetch-Mode : navigate
        Sec-Fetch-Site : none
        Sec-Fetch-User : ?1
        If-None-Match : "65cbc605-4716"

[ Request details ------------------------------------------- ]
    Request: GET status: 200 OK
    URL: https://duckduckgo.com/?t=h_
    [ Request headers --------------------------------------- ]
        Host : duckduckgo.com
        User-Agent : Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101
            Firefox/91.0
        Accept : text/html,application/xhtml+xml,application/xml;q=0.9,
            image/webp,*/*;q=0.8
        Accept-Language : en-GB,en;q=0.5
        Accept-Encoding : gzip, deflate, br
        Connection : keep-alive
        Cookie : l=wt-wt
        Upgrade-Insecure-Requests : 1
        Sec-Fetch-Dest : document
        Sec-Fetch-Mode : navigate
        Sec-Fetch-Site : none
        Sec-Fetch-User : ?1
        If-None-Match : "65cbc606-4716"
[ Request details ------------------------------------------- ]
    Request: GET status: 304 Not Modified
    URL: https://content-signature-2.cdn.mozilla.net/chains/remote-settings.
        content-signature.mozilla.org-2024-03-20-10-07-03.chain
    [ Request headers --------------------------------------- ]
        Host : content-signature-2.cdn.mozilla.net
        User-Agent : Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101
            Firefox/91.0
        Accept : */*
        Accept-Language : en-GB,en;q=0.5
        Accept-Encoding : gzip, deflate, br
        Connection : keep-alive
        Sec-Fetch-Dest : empty
        Sec-Fetch-Mode : cors
        Sec-Fetch-Site : cross-site
        If-Modified-Since : Tue, 30 Jan 2024 10:07:04 GMT
        If-None-Match : "b437816fe2de8ff3d429925523643815"

$ mv ~/.local/share/org.sailfishos/browser/.mozilla/ \
    ~/.local/share/org.sailfishos/browser/mozilla.bak
$ ps aux | grep browser
 4628 defaultu /usr/bin/invoker [...] --application=sailfish-browser
 4640 defaultu /usr/bin/firejail [...] --application=sailfish-browser
 4674 defaultu /usr/libexec/mapplauncherd/booster-browser
    --application=sailfish-browser
 4675 defaultu booster [browser]
 4702 defaultu grep browser
 6184 defaultu /usr/bin/invoker --type=silica-session [...]
    --application=jolla-email
 6243 defaultu /usr/bin/firejail [...] --application=sailfish-browser
 6248 defaultu /usr/bin/firejail [...] --application=jolla-email
 6442 defaultu /usr/libexec/mapplauncherd/booster-browser
    --application=jolla-email
 6452 defaultu booster [browser]
$ kill -1 4640
$ kill -1 6243

$ EMBED_CONSOLE=1 sailfish-browser
[...]
JSComp: EmbedLiteGlobalHelper.js loaded
[...]

function EmbedLiteGlobalHelper()
{
  L10nRegistry.registerSources([new FileSource(
                                   "0-mozembedlite",
                                   ["en-US", "fi", "ru"],
                                   "chrome://browser/content/localization/
                                   {locale}/")])

  Logger.debug("JSComp: EmbedLiteGlobalHelper.js loaded");
}

function EmbedLiteGlobalHelper()
{
  ActorManagerParent.flush();

  L10nRegistry.registerSource(new FileSource(
                                  "0-mozembedlite",
                                  ["en-US", "fi", "ru"],
                                  "chrome://browser/content/localization/
                                  {locale}/"))

  Logger.debug("JSComp: EmbedLiteGlobalHelper.js loaded");
}

$ git log -S "ActorManagerParent" -1 -- jscomps/EmbedLiteGlobalHelper.js
commit 0bf2601425ec1d8d639255d6a7c32231e7e38eae
Author: David Llewellyn-Jones <david.llewellyn-jones@jolla.com>
Date:   Thu Nov 23 21:55:13 2023 +0000

    Remove EmbedLiteGlobalHelper.js errors
    
    Makes three changes to address errors that were coming from
    EmbedLiteGlobalHelper.js:
    
    1. Use ComponentUtils.generateNSGetFactory() instead of
       XPCOMUtils.generateNSGetFactory().
    
    2. Remove call to ActorManagerParent.flush(). See Bug 1649843.
    
    3. Use L10nRegistry.registerSources() instead of
       L10nRegistry.registerSource(). See Bug 1648631.
    
    See the following related upstream changes:
    
    https://phabricator.services.mozilla.com/D95206
    
    https://phabricator.services.mozilla.com/D81243

JavaScript error: file:///usr/lib64/mozembedlite/components/
    EmbedLiteGlobalHelper.js,
    line 32: TypeError: ActorManagerParent.flush is not a function
JavaScript error: file:///usr/lib64/mozembedlite/components/
    EmbedLiteGlobalHelper.js,
    line 34: TypeError: L10nRegistry.registerSource is not a function

$ sailfish-browser
[D] unknown:0 - Using Wayland-EGL
[...]
Created LOG for EmbedLite
ACTOR: addJSProcessActors
ACTOR: RegisterProcessActor: 
ACTOR: RegisterProcessActor: 
ACTOR: RegisterProcessActor: 
ACTOR: addJSWindowActors
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
AJavaScript error: file:///usr/lib64/mozembedlite/components/
    EmbedLiteGlobalHelper.js, line 31: TypeError: ActorManagerParent.flush
    is not a function
CTOR: RegisterWindowActor: 
ACTOR: RegisterWindowActor: 
Created LOG for EmbedPrefs
Created LOG for EmbedLiteLayerManager
ACTOR: Getting LoginManager
ACTOR: Getting LoginManager
ACTOR: Getting LoginManager
ACTOR: Getting LoginManager
Call EmbedLiteApp::StopChildThread()

function EmbedLiteGlobalHelper()
{
  // Touch ActorManagerParent so that it gets initialised
  var actor = new ActorManagerParent();

  L10nRegistry.registerSources([new FileSource(
                                   "0-mozembedlite",
                                   ["en-US", "fi", "ru"],
                                   "chrome://browser/content/localization/
                                   {locale}/")])

  Logger.debug("JSComp: EmbedLiteGlobalHelper.js loaded");
}

$ sailfish-browser
[D] unknown:0 - Using Wayland-EGL
[...]
Created LOG for EmbedLiteTrace
[D] onCompleted:105 - ViewPlaceholder requires a SilicaFlickable parent
Created LOG for EmbedLite
ACTOR: addJSProcessActors
ACTOR: RegisterProcessActor: 
ACTOR: RegisterProcessActor: 
ACTOR: RegisterProcessActor: 
ACTOR: addJSWindowActors
ACTOR: RegisterWindowActor: 
[...]
ACTOR: RegisterWindowActor: 
Created LOG for EmbedPrefs
Created LOG for EmbedLiteLayerManager
ACTOR: Getting LoginManager
ACTOR: Getting LoginManager
ACTOR: Getting LoginManager
ACTOR: Getting LoginManager
Call EmbedLiteApp::StopChildThread()

$ MOZ_LOG="BrowsingContext:5" sailfish-browser
[D] unknown:0 - Using Wayland-EGL
library "libutils.so" not found
library "libcutils.so" not found
library "libhardware.so" not found
library "android.hardware.graphics.mapper@2.0.so" not found
library "android.hardware.graphics.mapper@2.1.so" not found
library "android.hardware.graphics.mapper@3.0.so" not found
library "android.hardware.graphics.mapper@4.0.so" not found
library "libc++.so" not found
library "libhidlbase.so" not found
library "libgralloctypes.so" not found
library "android.hardware.graphics.common@1.2.so" not found
library "libion.so" not found
library "libz.so" not found
library "libhidlmemory.so" not found
library "android.hidl.memory@1.0.so" not found
library "vendor.qti.qspmhal@1.0.so" not found
greHome from GRE_HOME:/usr/bin
libxul.so is not found, in /usr/bin/libxul.so
Created LOG for EmbedLiteTrace
[D] onCompleted:105 - ViewPlaceholder requires a SilicaFlickable parent
Created LOG for EmbedLite
Created LOG for EmbedPrefs
Created LOG for EmbedLiteLayerManager
[Parent 4610: Unnamed thread 7908002670]: D/BrowsingContext Creating 0x00000003
    in Parent
[Parent 4610: Unnamed thread 7908002670]: D/BrowsingContext Parent: Connecting
    0x00000003 to 0x00000000 (private=0, remote=0, fission=0, oa=)
ACTOR: Getting LoginManager
[Parent 4610: Unnamed thread 7908002670]: D/BrowsingContext ACTOR: GetActor: 
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 542:
    NotFoundError: WindowGlobalChild.getActor: No such JSWindowActor
    'LoginManager'
ACTOR: Getting LoginManager
[Parent 4610: Unnamed thread 7908002670]: D/BrowsingContext ACTOR: GetActor: 
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 542:
    NotFoundError: WindowGlobalChild.getActor: No such JSWindowActor
    'LoginManager'
[Parent 4610: Unnamed thread 7908002670]: D/BrowsingContext Parent: Detaching
    0x00000003 from 0x00000000
Call EmbedLiteApp::StopChildThread()
Redirecting call to abort() to mozalloc_abort

$ MOZ_LOG="BrowsingContext:5" sailfish-browser 2>&1 | grep -E "ACTOR:|error"
ACTOR: Getting LoginManager
[Parent 4720: Unnamed thread 7668002670]: D/BrowsingContext ACTOR: GetActor: 
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 542:
    NotFoundError: WindowGlobalChild.getActor: No such JSWindowActor
    'LoginManager'
ACTOR: Getting LoginManager
[Parent 4720: Unnamed thread 7668002670]: D/BrowsingContext ACTOR: GetActor: 
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 542:
    NotFoundError: WindowGlobalChild.getActor: No such JSWindowActor
    'LoginManager'

$ MOZ_LOG="BrowsingContext:5" gdb sailfish-browser
GNU gdb (GDB) Mer (8.2.1+git9)
[...]
(gdb) b JSActorService::RegisterWindowActor
Function "JSActorService::RegisterWindowActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (JSActorService::RegisterWindowActor) pending.
(gdb) b JSActorService::UnregisterWindowActor
Function "JSActorService::UnregisterWindowActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (JSActorService::UnregisterWindowActor) pending.
(gdb) b JSActorService::RegisterProcessActor
Function "JSActorService::RegisterProcessActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 3 (JSActorService::RegisterProcessActor) pending.
(gdb) b JSActorService::UnregisterProcessActor
Function "JSActorService::UnregisterProcessActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 4 (JSActorService::UnregisterProcessActor) pending.
(gdb) r
[...]
ACTOR: Getting LoginManager
[Parent 8108: Unnamed thread 7fc0002670]: D/BrowsingContext ACTOR: GetActor: 
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 542:
    NotFoundError: WindowGlobalChild.getActor: No such JSWindowActor
    'LoginManager'
[...]
ACTOR: Getting LoginManager
[Parent 8108: Unnamed thread 7fc0002670]: D/BrowsingContext ACTOR: GetActor: 
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 542:
    NotFoundError: WindowGlobalChild.getActor: No such JSWindowActor
    'LoginManager'
[Parent 8108: Unnamed thread 7fc0002670]: D/BrowsingContext Parent: Detaching
    0x00000003 from 0x00000000
Call EmbedLiteApp::StopChildThread()
Redirecting call to abort() to mozalloc_abort
[...]
(gdb) info break
Num Type       Disp Enb  What
1   breakpoint keep y    in mozilla::dom::JSActorService::RegisterWindowActor
                            (nsTSubstring<char> const&, mozilla::dom::
                            WindowActorOptions const&, mozilla::ErrorResult&) 
                         at dom/ipc/jsactor/JSActorService.cpp:60
2   breakpoint keep y    in mozilla::dom::JSActorService::UnregisterWindowActor
                            (nsTSubstring<char> const&) 
                         at dom/ipc/jsactor/JSActorService.cpp:109
3   breakpoint keep y    in mozilla::dom::JSActorService::RegisterProcessActor
                            (nsTSubstring<char> const&, mozilla::dom::
                            ProcessActorOptions const&, mozilla::ErrorResult&) 
                         at dom/ipc/jsactor/JSActorService.cpp:231
4   breakpoint keep y    in mozilla::dom::JSActorService::UnregisterProcessActor
                            (nsTSubstring<char> const&) 
                         at dom/ipc/jsactor/JSActorService.cpp:275
(gdb) 

$ gdb sailfish-browser 
GNU gdb (GDB) Mer (8.2.1+git9)
[...]
(gdb) b JSActorService::RegisterWindowActor
Function "JSActorService::RegisterWindowActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (JSActorService::RegisterWindowActor) pending.
(gdb) b JSActorService::UnregisterWindowActor
Function "JSActorService::UnregisterWindowActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (JSActorService::UnregisterWindowActor) pending.
(gdb) b JSActorService::RegisterProcessActor
Function "JSActorService::RegisterProcessActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 3 (JSActorService::RegisterProcessActor) pending.
(gdb) b JSActorService::UnregisterProcessActor
Function "JSActorService::UnregisterProcessActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 4 (JSActorService::UnregisterProcessActor) pending.
(gdb) r
[...]
Thread 10 "GeckoWorkerThre" hit Breakpoint 1, mozilla::dom::JSActorService::
    RegisterWindowActor (this=this@entry=0x7f80480850, aName=..., aOptions=..., 
    aRv=...) at dom/ipc/JSActorService.cpp:51
51	                                         ErrorResult& aRv) {
(gdb) handle SIGPIPE nostop
Signal        Stop	Print	Pass to program	Description
SIGPIPE       No	Yes	Yes		Broken pipe
(gdb) p aName
$1 = (const nsACString &) @0x7fa69e3d80: {<mozilla::detail::nsTStringRepr
    <char>> = {mData = 0x7fa69e3d94 "AboutHttpsOnlyError", mLength = 19, 
    mDataFlags = (mozilla::detail::StringDataFlags::TERMINATED |
    mozilla::detail::StringDataFlags::INLINE), 
    mClassFlags = mozilla::detail::StringClassFlags::INLINE},
    static kMaxCapacity = 2147483637}
(gdb) p aName.mData
$2 = (mozilla::detail::nsTStringRepr<char>::char_type *) 0x7fa69e3d94
    "AboutHttpsOnlyError"
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 1, mozilla::dom::JSActorService::
    RegisterWindowActor (this=this@entry=0x7f80480850, aName=..., aOptions=..., 
    aRv=...) at dom/ipc/JSActorService.cpp:51
51	                                         ErrorResult& aRv) {
(gdb) p aName.mData
$3 = (mozilla::detail::nsTStringRepr<char>::char_type *) 0x7fa69e3d94
    "AudioPlayback"
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 1, mozilla::dom::JSActorService::
    RegisterWindowActor (this=this@entry=0x7f80480850, aName=..., aOptions=..., 
    aRv=...) at dom/ipc/JSActorService.cpp:51
51	                                         ErrorResult& aRv) {
(gdb) p aName.mData
$4 = (mozilla::detail::nsTStringRepr<char>::char_type *) 0x7fa69e3d94
    "AutoComplete"
(gdb) c
[...] 

There are dozens more of them. But also, crucially, this one: 

Thread 10 "GeckoWorkerThre" hit Breakpoint 1, mozilla::dom::JSActorService:: RegisterWindowActor (this=this@entry=0x7f80480850, aName=..., aOptions=..., aRv=...) at dom/ipc/JSActorService.cpp:51 51 ErrorResult& aRv) { (gdb) p aName.mData $17 = (mozilla::detail::nsTStringRepr<char>::char_type *) 0x7fa69e3a84 "LoginManager" (gdb) bt #0 mozilla::dom::JSActorService::RegisterWindowActor (this=this@entry=0x7f80480850, aName=..., aOptions=..., aRv=...) at dom/ipc/JSActorService.cpp:51 #1 0x0000007fba9881b0 in mozilla::dom::ChromeUtils::RegisterWindowActor (aGlobal=..., aName=..., aOptions=..., aRv=...) at dom/base/ChromeUtils.cpp:1243 #2 0x0000007fbae8b4f4 in mozilla::dom::ChromeUtils_Binding::registerWindowActor (cx_=<optimized out>, argc=<optimized out>, vp=0x7fa69e3b00) at ChromeUtilsBinding.cpp:4263 #3 0x0000007f00460260 in ?? () #4 0x0000007fbcb1ba80 in Interpret (cx=0x7fa69e3ad0, state=...) at js/src/vm/Activation.h:541 #5 0x0000007fbcb1ba80 in Interpret (cx=0x7f802270c0, state=...) at js/src/vm/Activation.h:541 #6 0x0000000000000000 in ?? () Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) 

(gdb) b ChromeUtils::RegisterWindowActor
Breakpoint 5 at 0x7ff2c9a0d8: file dom/base/ChromeUtils.cpp, line 1350.
(gdb) b ChromeUtils_Binding::registerWindowActor
Breakpoint 6 at 0x7ff31bf858: file ChromeUtilsBinding.cpp, line 5237.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/sailfish-browser 
[...]

  addJSProcessActors(actors) {
    dump("ACTOR: addJSProcessActors\n");
    this._addActors(actors, "JSProcessActor");
  },
  addJSWindowActors(actors) {
    dump("ACTOR: addJSWindowActors\n");
    this._addActors(actors, "JSWindowActor");
  },

$ EMBED_CONSOLE=1 sailfish-browser
[D] unknown:0 - Using Wayland-EGL
library "libGLESv2_adreno.so" not found
library "eglSubDriverAndroid.so" not found
greHome from GRE_HOME:/usr/bin
libxul.so is not found, in /usr/bin/libxul.so
Created LOG for EmbedLiteTrace
[D] onCompleted:105 - ViewPlaceholder requires a SilicaFlickable parent
Created LOG for EmbedLite
JSComp: EmbedLiteConsoleListener.js loaded
JSComp: ContentPermissionManager.js loaded
JSComp: EmbedLiteChromeManager.js loaded
JSComp: EmbedLiteErrorPageHandler.js loaded
JSComp: EmbedLiteFaviconService.js loaded
ACTOR: addJSProcessActors
ACTOR: addJSWindowActors
JSComp: EmbedLiteGlobalHelper.js loaded
EmbedLiteGlobalHelper app-startup
[..]

$ sailfish-browser 2>&1 | grep "ACTOR:"
ACTOR: addJSProcessActors
ACTOR: addJSWindowActors

$ EMBED_CONSOLE=1 sailfish-browser
[D] unknown:0 - Using Wayland-EGL
library "libutils.so" not found
library "libcutils.so" not found
library "libhardware.so" not found
library "android.hardware.graphics.mapper@2.0.so" not found
library "android.hardware.graphics.mapper@2.1.so" not found
library "android.hardware.graphics.mapper@3.0.so" not found
library "android.hardware.graphics.mapper@4.0.so" not found
library "libc++.so" not found
library "libhidlbase.so" not found
library "libgralloctypes.so" not found
library "android.hardware.graphics.common@1.2.so" not found
library "libion.so" not found
library "libz.so" not found
library "libhidlmemory.so" not found
library "android.hidl.memory@1.0.so" not found
library "vendor.qti.qspmhal@1.0.so" not found
greHome from GRE_HOME:/usr/bin
libxul.so is not found, in /usr/bin/libxul.so
Created LOG for EmbedLiteTrace
[D] onCompleted:105 - ViewPlaceholder requires a SilicaFlickable parent
Created LOG for EmbedLite
JSComp: EmbedLiteConsoleListener.js loaded
JSComp: ContentPermissionManager.js loaded
JSComp: EmbedLiteChromeManager.js loaded
JSComp: EmbedLiteErrorPageHandler.js loaded
JSComp: EmbedLiteFaviconService.js loaded
JSComp: EmbedLiteGlobalHelper.js loaded
EmbedLiteGlobalHelper app-startup
[...]

$ sailfish-browser 2>&1 | grep "ACTOR:"
ACTOR: Getting LoginManager
ACTOR: Getting LoginManager

ChromeUtils.defineModuleGetter(
  this,
  "ActorManagerParent",
  "resource://gre/modules/ActorManagerParent.jsm"
);

  // initialization (called on application startup)
  _init: function BG__init() {
[...]
    ActorManagerParent.addJSProcessActors(JSPROCESSACTORS);
    ActorManagerParent.addJSWindowActors(JSWINDOWACTORS);
    ActorManagerParent.addLegacyActors(LEGACY_ACTORS);
    ActorManagerParent.flush();
[...]
  },

//ChromeUtils.defineModuleGetter(
//  this,
//  "ActorManagerParent",
//  "resource://gre/modules/ActorManagerParent.jsm"
//);

Services.scriptloader.loadSubScript("chrome://embedlite/content/Logger.js");

// Common helper service

function EmbedLiteGlobalHelper()
{
  //ActorManagerParent.flush();
[...]

$ sailfish-browser
[D] unknown:0 - Using Wayland-EGL
library "libGLESv2_adreno.so" not found
library "eglSubDriverAndroid.so" not found
greHome from GRE_HOME:/usr/bin
libxul.so is not found, in /usr/bin/libxul.so
Created LOG for EmbedLiteTrace
[D] onCompleted:105 - ViewPlaceholder requires a SilicaFlickable parent
Created LOG for EmbedLite
Created LOG for EmbedPrefs
Created LOG for EmbedLiteLayerManager
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 442:
    NotSupportedError: WindowGlobalChild.getActor: Could not get
    JSWindowActorProtocol: LoginManager is not registered

$ gdb sailfish-browser
GNU gdb (GDB) Mer (8.2.1+git9)
[...]
(gdb) b JSActorService::RegisterWindowActor
Function "JSActorService::RegisterWindowActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (JSActorService::RegisterWindowActor) pending.
(gdb) b JSActorService::UnregisterWindowActor
Function "JSActorService::UnregisterWindowActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (JSActorService::UnregisterWindowActor) pending.
(gdb) b JSActorService::RegisterProcessActor
Function "JSActorService::RegisterProcessActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 3 (JSActorService::RegisterProcessActor) pending.
(gdb) b JSActorService::UnregisterProcessActor
Function "JSActorService::UnregisterProcessActor" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 4 (JSActorService::UnregisterProcessActor) pending.
(gdb) r
[...]

JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 541:
    NotFoundError: WindowGlobalChild.getActor:
    No such JSWindowActor 'LoginManager'

[defaultuser@Xperia10III gecko]$ sailfish-browser
[D] unknown:0 - Using Wayland-EGL
library "libutils.so" not found
library "libcutils.so" not found
library "libhardware.so" not found
library "android.hardware.graphics.mapper@2.0.so" not found
library "android.hardware.graphics.mapper@2.1.so" not found
library "android.hardware.graphics.mapper@3.0.so" not found
library "android.hardware.graphics.mapper@4.0.so" not found
library "libc++.so" not found
library "libhidlbase.so" not found
library "libgralloctypes.so" not found
library "android.hardware.graphics.common@1.2.so" not found
library "libion.so" not found
library "libz.so" not found
library "libhidlmemory.so" not found
library "android.hidl.memory@1.0.so" not found
library "vendor.qti.qspmhal@1.0.so" not found
greHome from GRE_HOME:/usr/bin
libxul.so is not found, in /usr/bin/libxul.so
Created LOG for EmbedLiteTrace
[D] onCompleted:105 - ViewPlaceholder requires a SilicaFlickable parent
Created LOG for EmbedLite
Created LOG for EmbedPrefs
Created LOG for EmbedLiteLayerManager
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 541:
    NotFoundError: WindowGlobalChild.getActor:
    No such JSWindowActor 'LoginManager'
JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 541:
    NotFoundError: WindowGlobalChild.getActor:
    No such JSWindowActor 'LoginManager'
Call EmbedLiteApp::StopChildThread()

$ grep -rIn ".getActor(\"" * --include="*.js*" | wc -l
167
$ grep -rIn ".getActor(\"LoginManager\")" * --include="*.js*" | wc -l
9

already_AddRefed<JSWindowActorChild> WindowGlobalChild::GetActor(
    JSContext* aCx, const nsACString& aName, ErrorResult& aRv) {

  MOZ_LOG(BrowsingContext::GetLog(), LogLevel::Debug, ("ACTOR: GetActor: ",
      PromiseFlatCString(aName)));

  return JSActorManager::GetActor(aCx, aName, aRv)
      .downcast<JSWindowActorChild>();
}

  static forWindow(window) {
    let windowGlobal = window.windowGlobalChild;
    if (windowGlobal) {
      dump("ACTOR: Getting LoginManager\n");
      return windowGlobal.getActor("LoginManager");
    }

    return null;
  }

void JSActorService::RegisterWindowActor(const nsACString& aName,
                                         const WindowActorOptions& aOptions,
                                         ErrorResult& aRv) {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(XRE_IsParentProcess());

  printf("ACTOR: RegisterWindowActor: %s", PromiseFlatCString(aName));
[...]

Warning: couldn't PurgeHistory. Was it a file download? TypeError:
    legacyHistory.PurgeHistory is not a function

JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 541:
    NotFoundError: WindowGlobalChild.getActor:
    No such JSWindowActor 'LoginManager'

JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 541:
    NotFoundError: WindowGlobalChild.getActor:
    No such JSWindowActor 'LoginManager'

  static forWindow(window) {
    let windowGlobal = window.windowGlobalChild;
    if (windowGlobal) {
      return windowGlobal.getActor("LoginManager");
    }

    return null;
  }

already_AddRefed<JSWindowActorChild> WindowGlobalChild::GetActor(
    JSContext* aCx, const nsACString& aName, ErrorResult& aRv) {
  return JSActorManager::GetActor(aCx, aName, aRv)
      .downcast<JSWindowActorChild>();
}

    {
        'cid': '{cb9e0de8-3598-4ed7-857b-827f011ad5d8}',
        'contract_ids': ['@mozilla.org/login-manager;1'],
        'jsm': 'resource://gre/modules/LoginManager.jsm',
        'constructor': 'LoginManager',
    },

    {
        'js_name': 'logins',
        'cid': '{cb9e0de8-3598-4ed7-857b-827f011ad5d8}',
        'contract_ids': ['@mozilla.org/login-manager;1'],
        'interfaces': ['nsILoginManager'],
        'jsm': 'resource://gre/modules/LoginManager.jsm',
        'constructor': 'LoginManager',
    },

Warning: couldn't PurgeHistory. Was it a file download? TypeError: 
    legacyHistory.PurgeHistory is not a function

JavaScript error: resource://gre/modules/LoginManagerChild.jsm, line 541:
    NotFoundError: WindowGlobalChild.getActor:
    No such JSWindowActor 'LoginManager'

  /**
   * Called to purge older documents from history.
   * Documents can be removed from session history for various
   * reasons. For example to  control memory usage of the browser, to
   * prevent users from loading documents from history, to erase evidence of
   * prior page loads etc...
   *
   * @param numEntries        The number of toplevel documents to be
   *                          purged from history. During purge operation,
   *                          the latest documents are maintained and older
   *                          'numEntries' documents are removed from history.
   * @throws                  <code>NS_SUCCESS_LOSS_OF_INSIGNIFICANT_DATA</code>
   *                          Purge was vetod.
   * @throws                  <code>NS_ERROR_FAILURE</code> numEntries is
   *                          invalid or out of bounds with the size of history.
   */
  void PurgeHistory(in long aNumEntries);

$ git log -1 -S "PurgeHistory" docshell/shistory/nsISHistory.idl
commit f9f96d23ca42f359e143d0ae98234021e86179a7
Author: Andreas Farre <farre@mozilla.com>
Date:   Wed Sep 16 14:51:01 2020 +0000

    Bug 1662410 - Part 1: Fix usage of ChildSHistory.legacySHistory . r=peterv
    
    ChildSHistory.legacySHistory isn't valid for content processes when
    session history in the parent is enabled. We try to fix this by either
    delegating to the parent by IPC or move the implementation partially
    or as a whole to the parent.
    
    Differential Revision: https://phabricator.services.mozilla.com/D89353

$ git diff f9f96d23ca42f359e143d0ae98234021e86179a7~ \
    f9f96d23ca42f359e143d0ae98234021e86179a7 \
    -- docshell/shistory/nsISHistory.idl
diff --git a/docshell/shistory/nsISHistory.idl b/docshell/shistory/
    nsISHistory.idl
index 3d914924c94d..1f5b9c5477e9 100644
--- a/docshell/shistory/nsISHistory.idl
+++ b/docshell/shistory/nsISHistory.idl
@@ -87,7 +87,7 @@ interface nsISHistory: nsISupports
    * @throws                  <code>NS_ERROR_FAILURE</code> numEntries is
    *                          invalid or out of bounds with the size of history.
    */
-  void PurgeHistory(in long aNumEntries);
+  void purgeHistory(in long aNumEntries);
 
   /**
    * Called to register a listener for the session history component.
@@ -255,7 +255,7 @@ interface nsISHistory: nsISupports
    * Collect docshellIDs from aEntry's children and remove those
    * entries from history.
    *
-   * @param aEntry           Children docshellID's will be collected from 
+   * @param aEntry           Children docshellID's will be collected from
    *                         this entry and passed to RemoveEntries as aIDs.
   */
   [noscript, notxpcom]
@@ -265,7 +265,7 @@ interface nsISHistory: nsISupports
   void Reload(in unsigned long aReloadFlags);
 
   [notxpcom] void EnsureCorrectEntryAtCurrIndex(in nsISHEntry aEntry);
-  
+
   [notxpcom] void EvictContentViewersOrReplaceEntry(in nsISHEntry aNewSHEntry,
       in bool aReplace);
 
   nsISHEntry createEntry();

      case "embedui:addhistory": {
        // aMessage.data contains: 1) list of 'links' loaded from DB, 2) current 'index'.

        let docShell = content.docShell;
        let sessionHistory = docShell.QueryInterface(Ci.nsIWebNavigation).sessionHistory;
        let legacyHistory = sessionHistory.legacySHistory;
        let ioService = Cc["@mozilla.org/network/io-service;1"].getService(Ci.nsIIOService);

        try {
          // Initially we load the current URL and that creates an unneeded entry in History -> purge it.
          if (legacyHistory.count > 0) {
            legacyHistory.PurgeHistory(1);
          }
        } catch (e) {
            Logger.warn("Warning: couldn't PurgeHistory. Was it a file download?", e);
        }

  // If we are an in-process browser, we want to set up our session history.
  if (mIsTopLevelContent && mOwnerContent->IsXULElement(nsGkAtoms::browser) &&
      !mOwnerContent->HasAttr(kNameSpaceID_None, nsGkAtoms::disablehistory)) {
    // XXX(nika): Set this up more explicitly?
    mPendingBrowsingContext->InitSessionHistory();
  }

  if (aBrowsingContext->IsTop()) {
    aBrowsingContext->InitSessionHistory();
  }

nsFrameLoader::LoadURI()
Document::InitializeFrameLoader()
Document::MaybeInitializeFinalizeFrameLoaders()
nsFrameLoader::ReallyStartLoading()
nsFrameLoader::ReallyStartLoadingInternal()
nsFrameLoader::EnsureRemoteBrowser()
nsFrameLoader::TryRemoteBrowser()
nsFrameLoader::TryRemoteBrowserInternal()
BrowsingContext::InitSessionHistory()

Thread 10 "GeckoWorkerThre" hit Breakpoint 4, nsFrameLoader::
    LoadURI (this=this@entry=0x7fc1419ef0, aURI=0x7fc15feb90,
    aTriggeringPrincipal=0x7fc11a47d0, aCsp=0x7ee8004780,
    aOriginalSrc=aOriginalSrc@entry=true) at dom/base/nsFrameLoader.cpp:600
600                                     bool aOriginalSrc) {
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 3, mozilla::dom::Document::
    InitializeFrameLoader (this=this@entry=0x7fc11a1960, 
    aLoader=aLoader@entry=0x7fc1419ef0) at dom/base/Document.cpp:8999
8999    nsresult Document::InitializeFrameLoader(nsFrameLoader* aLoader) {
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 2, mozilla::dom::Document::
    MaybeInitializeFinalizeFrameLoaders (this=0x7fc11a1960)
    at dom/base/Document.cpp:9039
9039    void Document::MaybeInitializeFinalizeFrameLoaders() {
(gdb) c
Continuing.
[...]
Thread 10 "GeckoWorkerThre" hit Breakpoint 9, nsFrameLoader::
    ReallyStartLoadingInternal (this=this@entry=0x7fc147afe0)
    at dom/base/nsFrameLoader.cpp:664
664     nsresult nsFrameLoader::ReallyStartLoadingInternal() {
(gdb) p mIsRemoteFrame
$3 = false
(gdb) 

  if (IsRemoteFrame()) {
    if (!EnsureRemoteBrowser()) {
      NS_WARNING("Couldn't create child process for iframe.");
      return NS_ERROR_FAILURE;
    }
[...]

bool nsFrameLoader::IsRemoteFrame() {
  if (mIsRemoteFrame) {
    MOZ_ASSERT(!GetDocShell(), "Found a remote frame with a DocShell");
    return true;
  }
  return false;
}

(gdb) p mPendingBrowsingContext.mRawPtr->mParentWindow.mRawPtr->
    mBrowsingContext.mRawPtr
$8 = (mozilla::dom::BrowsingContext *) 0x7fc0ba3f00

void
EmbedLiteViewChild::InitGeckoWindow(const uint32_t parentId,
                                    mozilla::dom::BrowsingContext
                                    *parentBrowsingContext,
                                    const bool isPrivateWindow,
                                    const bool isDesktopMode,
                                    const bool isHidden)
{
[...]
  RefPtr<BrowsingContext> browsingContext = BrowsingContext::CreateDetached
      (nullptr, parentBrowsingContext, nullptr, EmptyString(),
      BrowsingContext::Type::Content);
  browsingContext->SetUsePrivateBrowsing(isPrivateWindow); // Needs to be called before attaching
  browsingContext->EnsureAttached();
  browsingContext->InitSessionHistory();
[...]
  mWebBrowser = nsWebBrowser::Create(mChrome, mWidget, browsingContext,
                                     nullptr);

(gdb) bt
#0  nsFrameLoader::MaybeCreateDocShell (this=this@entry=0x7fc1476da0)
    at dom/base/nsFrameLoader.cpp:2241
#1  0x0000007ff2def6c0 in nsFrameLoader::ReallyStartLoadingInternal
    (this=this@entry=0x7fc1476da0)
    at dom/base/nsFrameLoader.cpp:751
#2  0x0000007ff2defa88 in nsFrameLoader::ReallyStartLoading
    (this=this@entry=0x7fc1476da0)
    at dom/base/nsFrameLoader.cpp:656
#3  0x0000007ff2d25198 in mozilla::dom::Document::
    MaybeInitializeFinalizeFrameLoaders (this=0x7fc11f88d0)
    at dom/base/Document.cpp:9068
#4  0x0000007ff2cceebc in mozilla::detail::RunnableMethodArguments<>::applyImpl
    <mozilla::dom::Document, void (mozilla::dom::Document::*)()>
    (mozilla::dom::Document*, void (mozilla::dom::Document::*)(),
    mozilla::Tuple<>&, std::integer_sequence<unsigned long>)
    (args=..., m=<optimized out>, o=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1151
#5  mozilla::detail::RunnableMethodArguments<>::apply<mozilla::dom::Document,
    void (mozilla::dom::Document::*)()> (m=<optimized out>, o=<optimized out>, 
    this=<optimized out>)
    at ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsThreadUtils.h:1154
[...]
#20 0x0000007ff4e7e564 in js::RunScript (cx=cx@entry=0x7fc0233bd0, state=...)
    at js/src/vm/Interpreter.cpp:395
#21 0x0000007ff4e7e9b0 in js::InternalCallOrConstruct (cx=cx@entry=0x7fc0233bd0,
    args=..., construct=construct@entry=js::NO_CONSTRUCT, 
    reason=reason@entry=js::CallReason::Call) at js/src/vm/Interpreter.cpp:543

Thread 10 "GeckoWorkerThre" hit Breakpoint 4, nsGenericHTMLFrameElement::
    GetContentWindowInternal (this=this@entry=0x7fba4f9560)
    at dom/html/nsGenericHTMLFrameElement.cpp:100
100       EnsureFrameLoader();
(gdb) bt
#0  nsGenericHTMLFrameElement::GetContentWindowInternal
    (this=this@entry=0x7fba4f9560)
    at dom/html/nsGenericHTMLFrameElement.cpp:100
#1  0x0000007ff39194bc in nsGenericHTMLFrameElement::GetContentWindow
    (this=this@entry=0x7fba4f9560)
    at dom/html/nsGenericHTMLFrameElement.cpp:116
#2  0x0000007ff3518bf0 in mozilla::dom::HTMLIFrameElement_Binding::
    get_contentWindow (cx=0x7fb82263f0, obj=..., void_self=0x7fba4f9560,
    args=...)
    at HTMLIFrameElementBinding.cpp:857
#3  0x0000007ff35b8290 in mozilla::dom::binding_detail::GenericGetter
    <mozilla::dom::binding_detail::NormalThisPolicy, mozilla::dom::
    binding_detail::ThrowExceptions> (cx=0x7fb82263f0, argc=<optimized out>,
    vp=<optimized out>)
    at dist/include/js/CallArgs.h:245
#4  0x0000007ff4e19610 in CallJSNative (args=..., reason=js::CallReason::Getter, 
    native=0x7ff35b80c0 <mozilla::dom::binding_detail::GenericGetter
    <mozilla::dom::binding_detail::NormalThisPolicy, mozilla::dom::
    binding_detail::ThrowExceptions>(JSContext*, unsigned int, JS::Value*)>,
    cx=0x7fb82263f0)
    at dist/include/js/CallArgs.h:285
#5  js::InternalCallOrConstruct (cx=cx@entry=0x7fb82263f0, args=...,
    construct=construct@entry=js::NO_CONSTRUCT, 
    reason=reason@entry=js::CallReason::Getter) at js/src/vm/Interpreter.cpp:585
#6  0x0000007ff4e1a268 in InternalCall (reason=js::CallReason::Getter, args=...,
    cx=0x7fb82263f0)
    at js/src/vm/Interpreter.cpp:648
#7  js::Call (reason=js::CallReason::Getter, rval=..., args=..., thisv=...,
    fval=..., cx=0x7fb82263f0)
    at js/src/vm/Interpreter.cpp:665
#8  js::CallGetter (cx=cx@entry=0x7fb82263f0, thisv=..., getter=...,
    getter@entry=..., rval=...)
    at js/src/vm/Interpreter.cpp:789
[...]
#44 0x0000007fefa864ac in QThread::exec() () from /usr/lib64/libQt5Core.so.5
#45 0x0000007fefa8b0e8 in ?? () from /usr/lib64/libQt5Core.so.5
#46 0x0000007fef971a4c in ?? () from /lib64/libpthread.so.0
#47 0x0000007fef65b89c in ?? () from /lib64/libc.so.6
(gdb) 

Thread 8 "GeckoWorkerThre" hit Breakpoint 3, nsFrameLoader::GetBrowsingContext
    (this=0x7f89886f80)
    at dom/base/nsFrameLoader.cpp:3194
3194      if (IsRemoteFrame()) {
(gdb) bt
#0  nsFrameLoader::GetBrowsingContext (this=0x7f89886f80)
    at dom/base/nsFrameLoader.cpp:3194
#1  0x0000007fbb5ad250 in mozilla::dom::HTMLIFrameElement::
    MaybeStoreCrossOriginFeaturePolicy (this=0x7f895858f0)
    at dom/html/HTMLIFrameElement.cpp:252
#2  mozilla::dom::HTMLIFrameElement::MaybeStoreCrossOriginFeaturePolicy
    (this=0x7f895858f0)
    at dom/html/HTMLIFrameElement.cpp:241
#3  0x0000007fbb5ad390 in mozilla::dom::HTMLIFrameElement::RefreshFeaturePolicy
    (this=0x7f895858f0, aParseAllowAttribute=aParseAllowAttribute@entry=true)
    at dom/html/HTMLIFrameElement.cpp:329
#4  0x0000007fbb5ad4b8 in mozilla::dom::HTMLIFrameElement::BindToBrowsingContext
    (this=<optimized out>, aBrowsingContext=<optimized out>)
    at dom/html/HTMLIFrameElement.cpp:72
#5  0x0000007fbc7abf60 in mozilla::dom::BrowsingContext::Embed
    (this=<optimized out>)
    at docshell/base/BrowsingContext.cpp:505
#6  0x0000007fbaae320c in nsFrameLoader::MaybeCreateDocShell (this=0x7f89886f80)
    at dist/include/mozilla/RefPtr.h:313
#7  0x0000007fbaae5468 in nsFrameLoader::ReallyStartLoadingInternal
    (this=this@entry=0x7f89886f80)
    at dom/base/nsFrameLoader.cpp:612
#8  0x0000007fbaae5864 in nsFrameLoader::ReallyStartLoading (
dwarf2read.c:10473: internal-error: process_die_scope::process_die_scope
    (die_info*, dwarf2_cu*): Assertion `!m_die->in_process' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.

Breakpoint 3 at 0x7ff3925d4c: file dom/html/HTMLIFrameElement.cpp, line 221.
(gdb) b HTMLIFrameElement::MaybeStoreCrossOriginFeaturePolicy
Note: breakpoint 3 also set at pc 0x7ff3925d4c.
Breakpoint 4 at 0x7ff3925d4c: file dom/html/HTMLIFrameElement.cpp, line 221.
(gdb) b HTMLIFrameElement::RefreshFeaturePolicy
Breakpoint 5 at 0x7ff3925fb0: file dom/html/HTMLIFrameElement.cpp, line 266.
(gdb) b HTMLIFrameElement::BindToBrowsingContext
Breakpoint 6 at 0x7ff3926134: file dom/html/HTMLIFrameElement.cpp, line 70.
(gdb) b BrowsingContext::Embed
Breakpoint 7 at 0x7ff4ab2b0c: file ${PROJECT}/obj-build-mer-qt-xr/dist/include/
    mozilla/RefPtr.h, line 313.
(gdb) b nsFrameLoader::MaybeCreateDocShell
Breakpoint 8 at 0x7ff2dedc98: file dom/base/nsFrameLoader.cpp, line 2179.
(gdb) b  nsFrameLoader::ReallyStartLoadingInternal
Breakpoint 9 at 0x7ff2def63c: file dom/base/nsFrameLoader.cpp, line 664.
(gdb) info break
Num Type       Disp Enb What
2   breakpoint keep y   in nsFrameLoader::GetBrowsingContext() 
                        at dom/base/nsFrameLoader.cpp:3489
3   breakpoint keep y   in mozilla::dom::HTMLIFrameElement::
                           MaybeStoreCrossOriginFeaturePolicy() 
                        at dom/html/HTMLIFrameElement.cpp:221
4   breakpoint keep y   in mozilla::dom::HTMLIFrameElement::
                           MaybeStoreCrossOriginFeaturePolicy() 
                        at dom/html/HTMLIFrameElement.cpp:221
5   breakpoint keep y   in mozilla::dom::HTMLIFrameElement::
                           RefreshFeaturePolicy(bool) 
                        at dom/html/HTMLIFrameElement.cpp:266
6   breakpoint keep y   in mozilla::dom::HTMLIFrameElement::
                           BindToBrowsingContext(mozilla::dom::BrowsingContext*) 
                        at dom/html/HTMLIFrameElement.cpp:70
7   breakpoint keep y   in mozilla::dom::BrowsingContext::Embed() 
                        at ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/
                           RefPtr.h:313
8   breakpoint keep y   in nsFrameLoader::MaybeCreateDocShell() 
                        at dom/base/nsFrameLoader.cpp:2179
9   breakpoint keep y   in nsFrameLoader::ReallyStartLoadingInternal() 
                        at dom/base/nsFrameLoader.cpp:664
(gdb) r

Thread 10 "GeckoWorkerThre" hit Breakpoint 9, nsFrameLoader::
    ReallyStartLoadingInternal (this=this@entry=0x7fc160da30)
    at dom/base/nsFrameLoader.cpp:664
664     nsresult nsFrameLoader::ReallyStartLoadingInternal() {
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 8, nsFrameLoader::
    MaybeCreateDocShell(this=this@entry=0x7fc160da30)
    at dom/base/nsFrameLoader.cpp:2179
2179    nsresult nsFrameLoader::MaybeCreateDocShell() {
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 7, mozilla::dom::BrowsingContext::
    Embed (this=0x7fc161aa70)
    at docshell/base/BrowsingContext.cpp:711
711       if (auto* frame = HTMLIFrameElement::FromNode(mEmbedderElement)) {
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 6, mozilla::dom::HTMLIFrameElement::
    BindToBrowsingContext (this=0x7fc14db4c0)
    at dom/html/HTMLIFrameElement.cpp:70
70      void HTMLIFrameElement::BindToBrowsingContext(BrowsingContext*) {
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 5, mozilla::dom::HTMLIFrameElement::
    RefreshFeaturePolicy (this=0x7fc14db4c0, 
    aParseAllowAttribute=aParseAllowAttribute@entry=true) at
    dom/html/HTMLIFrameElement.cpp:266
266     void HTMLIFrameElement::RefreshFeaturePolicy(bool aParseAllowAttribute) {
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 3, mozilla::dom::HTMLIFrameElement::
    MaybeStoreCrossOriginFeaturePolicy (this=this@entry=0x7fc14db4c0)
    at dom/html/HTMLIFrameElement.cpp:221
221     void HTMLIFrameElement::MaybeStoreCrossOriginFeaturePolicy() {
(gdb) c
Continuing.

Thread 10 "GeckoWorkerThre" hit Breakpoint 2, nsFrameLoader::GetBrowsingContext
    (this=0x7fc160da30)
    at dom/base/nsFrameLoader.cpp:3489
3489      if (mNotifyingCrash) {
(gdb) 

BrowsingContext* nsFrameLoader::GetBrowsingContext() {
  if (mNotifyingCrash) {
    if (mPendingBrowsingContext && mPendingBrowsingContext->EverAttached()) {
      return mPendingBrowsingContext;
    }
    return nullptr;
  }
  if (IsRemoteFrame()) {
    Unused << EnsureRemoteBrowser();
  } else if (mOwnerContent) {
    Unused << MaybeCreateDocShell();
  }
  return GetExtantBrowsingContext();
}

(gdb) p mNotifyingCrash
$1 = false
(gdb) p mIsRemoteFrame
$2 = false
(gdb) p mOwnerContent
$3 = (mozilla::dom::Element *) 0x7fc14db4c0
(gdb) 

BrowsingContext* nsFrameLoader::GetBrowsingContext() {
  if (IsRemoteFrame()) {
    Unused << EnsureRemoteBrowser();
  } else if (mOwnerContent) {
    Unused << MaybeCreateDocShell();
  }
  return GetExtantBrowsingContext();
}

(gdb) p mIsRemoteFrame
$1 = false
(gdb) p mOwnerContent
$2 = (
dwarf2read.c:10473: internal-error: process_die_scope::process_die_scope
    (die_info*, dwarf2_cu*): Assertion `!m_die->in_process' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) n
(gdb) p (mOwnerContent != 0)
$3 = true
(gdb) 

Thread 10 "GeckoWorkerThre" hit Breakpoint 8, nsFrameLoader::MaybeCreateDocShell
    (this=this@entry=0x7fc160da30)
    at dom/base/nsFrameLoader.cpp:2179
2179    nsresult nsFrameLoader::MaybeCreateDocShell() {
(gdb) n
2180      if (GetDocShell()) {
(gdb) 
nsFrameLoader::GetBrowsingContext (this=0x7fc160da30) at dom/base/
    nsFrameLoader.cpp:3500
3500      return GetExtantBrowsingContext();
(gdb) 
mozilla::dom::HTMLIFrameElement::MaybeStoreCrossOriginFeaturePolicy
    (this=this@entry=0x7fc14db4c0)
    at dom/html/HTMLIFrameElement.cpp:232
232       RefPtr<BrowsingContext> browsingContext = mFrameLoader->
    GetBrowsingContext();
(gdb) 
234       if (!browsingContext || !browsingContext->IsContentSubframe()) {
(gdb) 
238       if (ContentChild* cc = ContentChild::GetSingleton()) {
(gdb) 
232       RefPtr<BrowsingContext> browsingContext = mFrameLoader->
    GetBrowsingContext();
(gdb) 
nsFrameLoader::MaybeCreateDocShell (this=this@entry=0x7fc160da30) at
    dom/base/nsFrameLoader.cpp:2237
2237      InvokeBrowsingContextReadyCallback();
(gdb) n
2239      mIsTopLevelContent = mPendingBrowsingContext->IsTopContent();
(gdb) 
2241      if (mIsTopLevelContent) {
(gdb) 
2252      nsCOMPtr<nsIDocShellTreeOwner> parentTreeOwner;
(gdb) 
1363    ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsCOMPtr.h:
    No such file or directory.
(gdb) 
859     in ${PROJECT}/obj-build-mer-qt-xr/dist/include/nsCOMPtr.h
(gdb) 
2258      RefPtr<EventTarget> chromeEventHandler;
(gdb) 
2259      bool parentIsContent = parentDocShell->GetBrowsingContext()->
    IsContent();
(gdb) 
2260      if (parentIsContent) {
(gdb) 
2263        parentDocShell->GetChromeEventHandler(getter_AddRefs
    (chromeEventHandler));
(gdb) 
289     ${PROJECT}/obj-build-mer-qt-xr/dist/include/mozilla/RefPtr.h:
    No such file or directory.
(gdb) 
2278      nsCOMPtr<nsPIDOMWindowOuter> newWindow = docShell->GetWindow();
(gdb) n
2285      newWindow->SetFrameElementInternal(mOwnerContent);
(gdb) 
2288      if (mOwnerContent->IsXULElement(nsGkAtoms::browser) &&
(gdb) 
2295      if (!docShell->Initialize()) {
(gdb) 
2301      NS_ENSURE_STATE(mOwnerContent);
(gdb) 

  // If we are an in-process browser, we want to set up our session history.
  if (mIsTopLevelContent && mOwnerContent->IsXULElement(nsGkAtoms::browser) &&
      !mOwnerContent->HasAttr(kNameSpaceID_None, nsGkAtoms::disablehistory)) {
    // XXX(nika): Set this up more explicitly?
    mPendingBrowsingContext->InitSessionHistory();
  }

(gdb) p mIsTopLevelContent 
$4 = false
(gdb) n
2304      if (mIsTopLevelContent && mOwnerContent->IsXULElement(nsGkAtoms::browser) &&
(gdb) 
2315      HTMLIFrameElement* iframe = HTMLIFrameElement::FromNode(mOwnerContent);
(gdb) 

  mIsTopLevelContent = mPendingBrowsingContext->IsTopContent();

  bool IsTopContent() const { return IsContent() && IsTop(); }
[...]
  bool IsContent() const { return mType == Type::Content; }
[...]
  bool IsTop() const { return !GetParent(); }

BrowsingContext* BrowsingContext::GetParent() const {
  return mParentWindow ? mParentWindow->GetBrowsingContext() : nullptr;
}

(gdb) p mPendingBrowsingContext.mRawPtr->mType
$5 = mozilla::dom::BrowsingContext::Type::Content
(gdb) p mPendingBrowsingContext.mRawPtr->mParentWindow
$6 = {mRawPtr = 0x7fc11bb430}
(gdb)