Add some plumbing for the color management of canvases

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.h

Index: third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.h
diff --git a/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.h b/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.h
index 10dab808eb768aa56acb2e5273836a1a5ea4dd48..a7065946006f107b5159063075a55e02e272b90d 100644
--- a/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.h
+++ b/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.h
@@ -203,7 +203,7 @@ private:
     CanvasRenderingContext::ContextType getContextType() const override { return CanvasRenderingContext::Context2d; }
     bool is2d() const override { return true; }
     bool isAccelerated() const override;
-    bool hasAlpha() const override { return m_hasAlpha; }
+    bool hasAlpha() const override { return CanvasRenderingContext::hasAlpha(); }
     void setIsHidden(bool) override;
     void stop() final;
     DECLARE_VIRTUAL_TRACE();
@@ -213,7 +213,6 @@ private:
     WebLayer* platformLayer() const override;
 
     Member<HitRegionManager> m_hitRegionManager;
-    bool m_hasAlpha;
     LostContextMode m_contextLostMode;
     bool m_contextRestorable;
     unsigned m_tryRestoreContextAttemptCount;