Introduce intercepting and handling devtools messages in the renderer.

content/browser/devtools/render_view_devtools_agent_host.h

Index: content/browser/devtools/render_view_devtools_agent_host.h
diff --git a/content/browser/devtools/render_view_devtools_agent_host.h b/content/browser/devtools/render_view_devtools_agent_host.h
index 61a4e6e87698b695b85f482cd803f2ab7383cee3..30bf45a52eeaf882f23e8486d8bab91bf8b0376d 100644
--- a/content/browser/devtools/render_view_devtools_agent_host.h
+++ b/content/browser/devtools/render_view_devtools_agent_host.h
@@ -18,6 +18,7 @@
 namespace content {
 
 class DevToolsAgentHostRvhObserver;
+class RendererOverridesHandler;
 class RenderViewHost;
 
 class CONTENT_EXPORT RenderViewDevToolsAgentHost
@@ -42,8 +43,6 @@ class CONTENT_EXPORT RenderViewDevToolsAgentHost
 
   // DevToolsAgentHostImpl overrides.
   virtual void DispatchOnInspectorBackend(const std::string& message) OVERRIDE;
-
-  // DevToolsAgentHostImpl implementation.
   virtual void SendMessageToAgent(IPC::Message* msg) OVERRIDE;
   virtual void NotifyClientAttaching() OVERRIDE;
   virtual void NotifyClientDetaching() OVERRIDE;
@@ -68,6 +67,7 @@ class CONTENT_EXPORT RenderViewDevToolsAgentHost
 
   RenderViewHost* render_view_host_;
   scoped_ptr<DevToolsAgentHostRvhObserver> rvh_observer_;
+  scoped_ptr<RendererOverridesHandler> overrides_handler_;
   std::string state_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewDevToolsAgentHost);