Get rid of extensions dependency from content\browser.

chrome/browser/extensions/extension_host.h

 // Copyright (c) 2011 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 CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 214 matching lines @@
 
   // Const version of below function.
   const Browser* GetBrowser() const;
 
   // ExtensionFunctionDispatcher::Delegate
   virtual Browser* GetBrowser();
   virtual gfx::NativeView GetNativeViewOfHost();
 
   // Message handlers.
   void OnRunFileChooser(const ViewHostMsg_RunFileChooser_Params& params);
+  void OnPostMessage(int port_id, const std::string& message);
 
   // Handles keyboard events that were not handled by HandleKeyboardEvent().
   // Platform specific implementation may override this method to handle the
   // event in platform specific way.
   virtual void UnhandledKeyboardEvent(const NativeWebKeyboardEvent& event) {}
 
   // Returns true if we're hosting a background page.
   // This isn't valid until CreateRenderView is called.
   bool is_background_page() const { return !view(); }
 
@@ skipping 53 matching lines @@
   // The time that the last javascript message was dismissed.
   base::TimeTicks last_javascript_message_dismissal_;
 
   // Whether to suppress all javascript messages.
   bool suppress_javascript_messages_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionHost);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_