www/firefox: use SkiaGL by default for OpenGL/WebRender compositing

Copy OS X behavior. If OpenGL compositing[1] doesn't crash OS or browser
SkiaGL canvas rendering is unlikely to make it worse. Mainly improves
FishIE Tank benchmark.

[1] layers.acceleration.force-enabled -> true in about:config or
    $ env MOZ_ACCELERATED=1 firefox -new-instance -profile `mktemp -d` ...

1 files changed, 85 insertions, 0 deletions

diff --git a/www/firefox/files/patch-bug1411481 b/www/firefox/files/patch-bug1411481
new file mode 100644
index 000000000000..d8e9992e264b
--- /dev/null
+++ b/www/firefox/files/patch-bug1411481
@@ -0,0 +1,85 @@
+commit 57a55d1c2d33
+Author: sotaro <sotaro.ikeda.g@gmail.com>
+Date:   Wed Mar 21 08:59:38 2018 +0900
+
+    Bug 1411481- Enable SkiaGL canvas usage on Mac r=jrmuizel
+---
+ dom/canvas/CanvasRenderingContext2D.cpp | 3 ++-
+ gfx/thebes/gfxPlatform.cpp              | 3 ++-
+ gfx/thebes/gfxPlatform.h                | 2 +-
+ gfx/thebes/gfxWindowsPlatform.cpp       | 7 +++++++
+ gfx/thebes/gfxWindowsPlatform.h         | 2 ++
+ 5 files changed, 14 insertions(+), 3 deletions(-)
+
+diff --git dom/canvas/CanvasRenderingContext2D.cpp dom/canvas/CanvasRenderingContext2D.cpp
+index ef3f868bdbf7..8666564b4d0c 100644
+--- dom/canvas/CanvasRenderingContext2D.cpp
++++ dom/canvas/CanvasRenderingContext2D.cpp
+@@ -1438,7 +1438,8 @@ CanvasRenderingContext2D::AllowOpenGLCanvas() const
+   // HTMLCanvasElement::GetCompositorBackendType would return LAYERS_NONE
+   // as well, so it wouldn't help much.
+ 
+-  return (mCompositorBackend == LayersBackend::LAYERS_OPENGL) &&
++  return (mCompositorBackend == LayersBackend::LAYERS_OPENGL ||
++          mCompositorBackend == LayersBackend::LAYERS_WR) &&
+     gfxPlatform::GetPlatform()->AllowOpenGLCanvas();
+ }
+ 
+diff --git gfx/thebes/gfxPlatform.cpp gfx/thebes/gfxPlatform.cpp
+index b9beea68d8c5..82635f9ab3ce 100644
+--- gfx/thebes/gfxPlatform.cpp
++++ gfx/thebes/gfxPlatform.cpp
+@@ -1386,7 +1386,8 @@ bool gfxPlatform::AllowOpenGLCanvas()
+   // so we let content process always assume correct compositor backend.
+   // The callers have to do the right thing.
+   bool correctBackend = !XRE_IsParentProcess() ||
+-    ((mCompositorBackend == LayersBackend::LAYERS_OPENGL) &&
++    ((mCompositorBackend == LayersBackend::LAYERS_OPENGL ||
++      mCompositorBackend == LayersBackend::LAYERS_WR) &&
+      (GetContentBackendFor(mCompositorBackend) == BackendType::SKIA));
+ 
+   if (gfxPrefs::CanvasAzureAccelerated() && correctBackend) {
+diff --git gfx/thebes/gfxPlatform.h gfx/thebes/gfxPlatform.h
+index c988eb1168a8..3bbf2b763f26 100644
+--- gfx/thebes/gfxPlatform.h
++++ gfx/thebes/gfxPlatform.h
+@@ -286,7 +286,7 @@ public:
+     /// asking for it, we will examine the commands in the first few seconds
+     /// of the canvas usage, and potentially change to accelerated or
+     /// non-accelerated canvas.
+-    bool AllowOpenGLCanvas();
++    virtual bool AllowOpenGLCanvas();
+     virtual void InitializeSkiaCacheLimits();
+ 
+     static bool AsyncPanZoomEnabled();
+diff --git gfx/thebes/gfxWindowsPlatform.cpp gfx/thebes/gfxWindowsPlatform.cpp
+index 9ba6f40c6cc0..4d65791d075f 100644
+--- gfx/thebes/gfxWindowsPlatform.cpp
++++ gfx/thebes/gfxWindowsPlatform.cpp
+@@ -509,6 +509,13 @@ gfxWindowsPlatform::UpdateRenderMode()
+   }
+ }
+ 
++bool
++gfxWindowsPlatform::AllowOpenGLCanvas()
++{
++  // OpenGL canvas is not supported on windows
++  return false;
++}
++
+ mozilla::gfx::BackendType
+ gfxWindowsPlatform::GetContentBackendFor(mozilla::layers::LayersBackend aLayers)
+ {
+diff --git gfx/thebes/gfxWindowsPlatform.h gfx/thebes/gfxWindowsPlatform.h
+index 47048de8f5f5..47ec0e9e5547 100644
+--- gfx/thebes/gfxWindowsPlatform.h
++++ gfx/thebes/gfxWindowsPlatform.h
+@@ -174,6 +174,8 @@ public:
+     void SchedulePaintIfDeviceReset() override;
+     void CheckForContentOnlyDeviceReset();
+ 
++    bool AllowOpenGLCanvas() override;
++
+     mozilla::gfx::BackendType GetContentBackendFor(mozilla::layers::LayersBackend aLayers) override;
+ 
+     mozilla::gfx::BackendType GetPreferredCanvasBackend() override;