implement getBufferSubDataAsync prototype

content/renderer/webgraphicscontext3d_provider_impl.cc

Index: content/renderer/webgraphicscontext3d_provider_impl.cc
diff --git a/content/renderer/webgraphicscontext3d_provider_impl.cc b/content/renderer/webgraphicscontext3d_provider_impl.cc
index dbdae19792963957c4de968f9b113a4e96a3c172..c46415fd96e09f5ea2ba6bd3c8eba37c0aec0670 100644
--- a/content/renderer/webgraphicscontext3d_provider_impl.cc
+++ b/content/renderer/webgraphicscontext3d_provider_impl.cc
@@ -46,4 +46,9 @@ void WebGraphicsContext3DProviderImpl::setErrorMessageCallback(
   provider_->ContextSupport()->SetErrorMessageCallback(c);
 }
 
+void WebGraphicsContext3DProviderImpl::signalQuery(
+    uint32_t query, const base::Closure& callback) {
+  provider_->ContextSupport()->SignalQuery(query, callback);
+}
+
 }  // namespace content