DevTools: pass agent host id to the renderer (Blink).

public/web/WebDevToolsAgentClient.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 @@
 struct WebDevToolsMessageData;
 struct WebRect;
 struct WebSize;
 
 class WebDevToolsAgentClient {
 public:
     virtual void sendMessageToInspectorFrontend(const WebString&) { }
     virtual void sendDebuggerOutput(const WebString&) { }
 
     // Returns the identifier of the entity hosting this agent.
+    // FIXME: remove once migrated to debuggerId().
     virtual int hostIdentifier() { return -1; }
 
+    // Returns unique identifier of the entity within process.
+    virtual int debuggerId() { return hostIdentifier(); }
+
     // Save the agent state in order to pass it later into WebDevToolsAgent::reattach
     // if the same client is reattached to another agent.
     virtual void saveAgentRuntimeState(const WebString&) { }
 
     class WebKitClientMessageLoop {
     public:
         virtual ~WebKitClientMessageLoop() { }
         virtual void run() = 0;
         virtual void quitNow() = 0;
     };
@@ skipping 37 matching lines @@
 
     virtual void setTouchEventEmulationEnabled(bool enabled, bool allowPinch) { }
 
 protected:
     ~WebDevToolsAgentClient() { }
 };
 
 } // namespace blink
 
 #endif