Hook up postMessages to WebRemoteFrameClient

public/web/WebRemoteFrameClient.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebRemoteFrameClient_h
 #define WebRemoteFrameClient_h
 
-#include "public/web/WebFrameClient.h"
+#include "public/web/WebDOMMessageEvent.h"
+#include "public/web/WebSecurityOrigin.h"
 
 namespace blink {
+class WebLocalFrame;
+class WebRemoteFrame;
 
-class WebRemoteFrameClient : public WebFrameClient {
+class WebRemoteFrameClient {
 public:
     // Notifies the embedder that a postMessage was issued to a remote frame.
     virtual void postMessageEvent(
         WebLocalFrame* sourceFrame,
         WebRemoteFrame* targetFrame,
         WebSecurityOrigin targetOrigin,
         WebDOMMessageEvent) = 0;
 };
 
 } // namespace blink
 
 #endif // WebRemoteFrameClient_h