Add IPC messages to transfer compositor protos

content/browser/renderer_host/render_widget_host_delegate.h

Index: content/browser/renderer_host/render_widget_host_delegate.h
diff --git a/content/browser/renderer_host/render_widget_host_delegate.h b/content/browser/renderer_host/render_widget_host_delegate.h
index a96428c7e17c92169b008823d697a51e563ad2f1..91b682cc1421216c5c6da5062ff7f4d415d1919a 100644
--- a/content/browser/renderer_host/render_widget_host_delegate.h
+++ b/content/browser/renderer_host/render_widget_host_delegate.h
@@ -163,6 +163,11 @@ class CONTENT_EXPORT RenderWidgetHostDelegate {
   virtual gfx::NativeViewAccessible GetParentNativeViewAccessible();
 #endif
 
+  // Called when the widget has sent a compositor proto.  This is used in Blimp
+  // mode with the RemoteChannel compositor.
+  virtual void ForwardCompositorProto(RenderWidgetHostImpl* render_widget_host,
+                                      const std::vector<uint8_t>& proto) {}
+
  protected:
   virtual ~RenderWidgetHostDelegate() {}
 };