Very basic Android browser-side compositing support.

content/browser/renderer_host/render_widget_host_impl.h

Index: content/browser/renderer_host/render_widget_host_impl.h
diff --git a/content/browser/renderer_host/render_widget_host_impl.h b/content/browser/renderer_host/render_widget_host_impl.h
index 55883dece235d97a3567533cf47a0c798e2ea24b..72e24cd62bc20746d584bc1103fee3e0caaba58f 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -45,6 +45,12 @@ struct WebCompositionUnderline;
 struct WebScreenInfo;
 }
 
+#if defined(OS_ANDROID)
+namespace WebKit {
+class WebLayer;
+}
+#endif
+
 namespace content {
 class BackingStore;
 class GestureEventFilter;
@@ -396,6 +402,11 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
     allow_privileged_mouse_lock_ = allow;
   }
 
+#if defined(OS_ANDROID)
+  virtual void AttachLayer(WebKit::WebLayer* layer) {}
+  virtual void RemoveLayer(WebKit::WebLayer* layer) {}
+#endif
+
  protected:
   virtual RenderWidgetHostImpl* AsRenderWidgetHostImpl() OVERRIDE;