cc: Route offscreen context creation for compositor to the browser.

ui/compositor/compositor.h

Index: ui/compositor/compositor.h
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index aa773b25e7c330e3ad10c1908666fe60ed8e61e5..2c0fd143105f9c3315c00f3ae139357656a88889 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -67,6 +67,15 @@ class COMPOSITOR_EXPORT ContextFactory {
   // with all compositors.
   virtual WebKit::WebGraphicsContext3D* CreateOffscreenContext() = 0;
 
+  virtual WebKit::WebGraphicsContext3D*
+      OffscreenContextForMainThread() = 0;
+  virtual WebKit::WebGraphicsContext3D*
+      OffscreenContextForCompositorThread() = 0;
+  virtual GrContext*
+      OffscreenGrContextForMainThread() = 0;
+  virtual GrContext*
+      OffscreenGrContextForCompositorThread() = 0;
+
   // Destroys per-compositor data.
   virtual void RemoveCompositor(Compositor* compositor) = 0;
 };
@@ -81,6 +90,14 @@ class COMPOSITOR_EXPORT DefaultContextFactory : public ContextFactory {
   virtual cc::OutputSurface* CreateOutputSurface(
       Compositor* compositor) OVERRIDE;
   virtual WebKit::WebGraphicsContext3D* CreateOffscreenContext() OVERRIDE;
+  virtual WebKit::WebGraphicsContext3D*
+      OffscreenContextForMainThread() OVERRIDE;
+  virtual WebKit::WebGraphicsContext3D*
+      OffscreenContextForCompositorThread() OVERRIDE;
+  virtual GrContext*
+      OffscreenGrContextForMainThread() OVERRIDE;
+  virtual GrContext*
+      OffscreenGrContextForCompositorThread() OVERRIDE;
   virtual void RemoveCompositor(Compositor* compositor) OVERRIDE;
 
   bool Initialize();
@@ -261,6 +278,13 @@ class COMPOSITOR_EXPORT Compositor
   virtual scoped_ptr<cc::OutputSurface>
       createOutputSurface() OVERRIDE;
   virtual void didRecreateOutputSurface(bool success) OVERRIDE;
+  virtual WebKit::WebGraphicsContext3D*
+      offscreenContext3dForMainThread() OVERRIDE;
+  virtual WebKit::WebGraphicsContext3D*
+      offscreenContext3dForCompositorThread() OVERRIDE;
+  virtual GrContext* offscreenGrContextForMainThread() OVERRIDE;
+  virtual GrContext* offscreenGrContextForCompositorThread()
+      OVERRIDE;
   virtual scoped_ptr<cc::InputHandler> createInputHandler() OVERRIDE;
   virtual void willCommit() OVERRIDE;
   virtual void didCommit() OVERRIDE;