Enable RGBA_4444 in GpuRasterBufferProvider

cc/resources/resource_provider.h

Index: cc/resources/resource_provider.h
diff --git a/cc/resources/resource_provider.h b/cc/resources/resource_provider.h
index df3c5b85fb6bf1fa476f80761982df271ce19fa2..50aa24ec31486caec28f1df641e616e9933d9039 100644
--- a/cc/resources/resource_provider.h
+++ b/cc/resources/resource_provider.h
@@ -109,7 +109,11 @@ class CC_EXPORT ResourceProvider
   }
   size_t num_resources() const { return resources_.size(); }
 
-  bool IsResourceFormatSupported(ResourceFormat format) const;
+  bool IsTextureFormatSupported(ResourceFormat format) const;
+
+  // Returns true if the provided |format| can be used as a render buffer.
+  // Note that render buffer support implies texture support.
+  bool IsRenderBufferFormatSupported(ResourceFormat format) const;
 
   // Checks whether a resource is in use by a consumer.
   bool InUseByConsumer(ResourceId id);