[DevTools] Add power profiler and power overview in timeline panel.

public/web/WebDevToolsFrontendClient.h

 /*
  * Copyright (C) 2009 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 29 matching lines @@
 class WebDevToolsFrontendClient {
 public:
     WebDevToolsFrontendClient() { }
 
     virtual void sendMessageToBackend(const WebString&) { }
 
     virtual void sendMessageToEmbedder(const WebString&) { }
 
     virtual bool isUnderTest() { return false; }
 
+    virtual void checkPowerProfileSupportedStatus() { }
+    virtual void startPowerProfile() { }
+    virtual void stopPowerProfile() { }
+    virtual void setPowerProfileResolution(unsigned) { }
+
 protected:
     virtual ~WebDevToolsFrontendClient() {}
 };
 
 } // namespace blink
 
 #endif