Replace JSON (de)serialization of extension messages with direct Value pickling.

chrome/browser/extensions/api/messaging/extension_message_port.h

 // Copyright (c) 2012 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_API_MESSAGING_EXTENSION_MESSAGE_PORT_H_
 #define CHROME_BROWSER_EXTENSIONS_API_MESSAGING_EXTENSION_MESSAGE_PORT_H_
 
 #include "chrome/browser/extensions/api/messaging/message_service.h"
 
 class GURL;
 
+namespace base {
+class ListValue;
+}
+
 namespace content {
 class RenderProcessHost;
 }  // namespace content
 
 namespace extensions {
 
 // A port that manages communication with an extension.
 class ExtensionMessagePort : public MessageService::MessagePort {
  public:
   ExtensionMessagePort(content::RenderProcessHost* process,
                        int routing_id,
                        const std::string& extension_id);
   virtual void DispatchOnConnect(
       int dest_port_id,
       const std::string& channel_name,
       const base::DictionaryValue& source_tab,
       const std::string& source_extension_id,
       const std::string& target_extension_id,
       const GURL& source_url) OVERRIDE;
   virtual void DispatchOnDisconnect(int source_port_id,
                                     const std::string& error_message) OVERRIDE;
-  virtual void DispatchOnMessage(const std::string& message,
+  virtual void DispatchOnMessage(scoped_ptr<base::ListValue> message,
                                  int target_port_id) OVERRIDE;
   virtual void IncrementLazyKeepaliveCount() OVERRIDE;
   virtual void DecrementLazyKeepaliveCount() OVERRIDE;
   virtual content::RenderProcessHost* GetRenderProcessHost() OVERRIDE;
 
  private:
   content::RenderProcessHost* process_;
   int routing_id_;
   std::string extension_id_;
   void* background_host_ptr_;  // used in IncrementLazyKeepaliveCount
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_MESSAGING_EXTENSION_MESSAGE_PORT_H_