Adds support for calling postMessage on a frame living in a different renderer.

content/public/browser/render_view_host_delegate.h

Index: content/public/browser/render_view_host_delegate.h
diff --git a/content/public/browser/render_view_host_delegate.h b/content/public/browser/render_view_host_delegate.h
index 4d437604a28e7dc5d459bdd677de6862c4c3856d..2d903472c2b73289fc9b7f654924d9d0ad2ebb79 100644
--- a/content/public/browser/render_view_host_delegate.h
+++ b/content/public/browser/render_view_host_delegate.h
@@ -30,6 +30,7 @@ struct NativeWebKeyboardEvent;
 struct ViewHostMsg_CreateWindow_Params;
 struct ViewHostMsg_DidFailProvisionalLoadWithError_Params;
 struct ViewHostMsg_FrameNavigate_Params;
+struct ViewMsg_PostMessage_Params;
 struct WebDropData;
 struct WebMenuItem;
 struct WebPreferences;
@@ -327,6 +328,11 @@ class CONTENT_EXPORT RenderViewHostDelegate : public IPC::Channel::Listener {
   // The page wants to close the active view in this tab.
   virtual void RouteCloseEvent(RenderViewHost* rvh) {}
 
+  // The page wants to post a message to the active view in this tab.
+  virtual void RouteMessageEvent(
+      RenderViewHost* rvh,
+      const ViewMsg_PostMessage_Params& params) {}
+
   // A javascript message, confirmation or prompt should be shown.
   virtual void RunJavaScriptMessage(RenderViewHost* rvh,
                                     const string16& message,