[DevTools] Switch from separate sendMessageToBackend method to using embedder.

Source/core/inspector/InspectorFrontendClient.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 27 matching lines @@
 namespace blink {
 
 class InspectorFrontendClient : public NoBaseWillBeGarbageCollectedFinalized<InspectorFrontendClient> {
 public:
     virtual ~InspectorFrontendClient() { }
 
     virtual void trace(Visitor*) { }
 
     virtual void windowObjectCleared() = 0;
 
-    virtual void sendMessageToBackend(const String&) = 0;
-
     virtual void sendMessageToEmbedder(const String&) = 0;
 
     virtual bool isUnderTest() = 0;
 
     virtual void dispose() = 0;
 };
 
 } // namespace blink
 
 #endif