Stop using the WebView::sharedGraphicsContext3D interface.

content/renderer/render_thread_impl.h

Index: content/renderer/render_thread_impl.h
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index acc7cf6dfdef5ea6bcf94e90cbe3318ac345b71e..daa68ef981b2040540b55a6903b4806101df4486 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -72,6 +72,7 @@ class AudioInputMessageFilter;
 class AudioMessageFilter;
 class AudioRendererMixerManager;
 class CompositorThread;
+class ContextProviderCommandBuffer;
 class DBMessageFilter;
 class DevToolsAgentFilter;
 class DomStorageDispatcher;
@@ -273,8 +274,9 @@ class CONTENT_EXPORT RenderThreadImpl : public RenderThread,
   // Handle loss of the shared GpuVDAContext3D context above.
   static void OnGpuVDAContextLoss();
 
-  scoped_refptr<cc::ContextProvider> OffscreenContextProviderForMainThread();
-  scoped_refptr<cc::ContextProvider>
+  scoped_refptr<ContextProviderCommandBuffer>
+      OffscreenContextProviderForMainThread();
+  scoped_refptr<ContextProviderCommandBuffer>
       OffscreenContextProviderForCompositorThread();
 
   // AudioRendererMixerManager instance which manages renderer side mixer