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

content/renderer/gpu/render_widget_compositor.h

Index: content/renderer/gpu/render_widget_compositor.h
diff --git a/content/renderer/gpu/render_widget_compositor.h b/content/renderer/gpu/render_widget_compositor.h
index 5cebe9fd0167f08f5dd95446154e472a7044e106..9f460aef0ffdd397e22956cf85f4974b02b5f583 100644
--- a/content/renderer/gpu/render_widget_compositor.h
+++ b/content/renderer/gpu/render_widget_compositor.h
@@ -83,6 +83,10 @@ class RenderWidgetCompositor : public WebKit::WebLayerTreeView,
   virtual void didCommitAndDrawFrame() OVERRIDE;
   virtual void didCompleteSwapBuffers() OVERRIDE;
   virtual void scheduleComposite() OVERRIDE;
+  virtual scoped_refptr<ui::ContextProvider>
+      OffscreenContextProviderForMainThread() OVERRIDE;
+  virtual scoped_refptr<ui::ContextProvider>
+      OffscreenContextProviderForCompositorThread() OVERRIDE;
 
 private:
   RenderWidgetCompositor(RenderWidget* widget,
@@ -94,6 +98,11 @@ private:
   RenderWidget* widget_;
   WebKit::WebLayerTreeViewClient* client_;
   scoped_ptr<cc::LayerTreeHost> layer_tree_host_;
+
+  class MainThreadContextProvider;
+  scoped_refptr<MainThreadContextProvider> contexts_main_thread_;
+  class CompositorThreadContextProvider;
+  scoped_refptr<CompositorThreadContextProvider> contexts_compositor_thread_;
 };
 
 }  // namespace content