implement getBufferSubDataAsync prototype

content/renderer/webgraphicscontext3d_provider_impl.h

Index: content/renderer/webgraphicscontext3d_provider_impl.h
diff --git a/content/renderer/webgraphicscontext3d_provider_impl.h b/content/renderer/webgraphicscontext3d_provider_impl.h
index 5adc7ff3303cf448db50666ecf659948cadb816b..80e491bf62de3dd0b5f39d9715f3baa95268d591 100644
--- a/content/renderer/webgraphicscontext3d_provider_impl.h
+++ b/content/renderer/webgraphicscontext3d_provider_impl.h
@@ -36,6 +36,7 @@ class CONTENT_EXPORT WebGraphicsContext3DProviderImpl
   void setLostContextCallback(const base::Closure&) override;
   void setErrorMessageCallback(
       const base::Callback<void(const char*, int32_t)>&) override;
+  void signalQuery(uint32_t, const base::Closure&) override;
 
   ContextProviderCommandBuffer* context_provider() const {
     return provider_.get();