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

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index 1009543931721c0368bafd5c2615fca5298b3ee4..f287c0eba0f09a61ccff4f2f6fbe11d9f46db19d 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -875,6 +875,7 @@ bool RenderViewHostImpl::OnMessageReceived(const IPC::Message& msg) {
                         OnMsgDidChangeNumWheelEvents)
     IPC_MESSAGE_HANDLER(ViewHostMsg_RouteCloseEvent,
                         OnMsgRouteCloseEvent)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_RouteMessageEvent, OnMsgRouteMessageEvent)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(ViewHostMsg_RunJavaScriptMessage,
                                     OnMsgRunJavaScriptMessage)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(ViewHostMsg_RunBeforeUnloadConfirm,
@@ -1281,6 +1282,12 @@ void RenderViewHostImpl::OnMsgRouteCloseEvent() {
   delegate_->RouteCloseEvent(this);
 }
 
+void RenderViewHostImpl::OnMsgRouteMessageEvent(
+    const ViewMsg_PostMessage_Params& params) {
+  // Give to the delegate to route to the active RenderViewHost.
+  delegate_->RouteMessageEvent(this, params);
+}
+
 void RenderViewHostImpl::OnMsgRunJavaScriptMessage(
     const string16& message,
     const string16& default_prompt,