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

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

Index: chrome/browser/extensions/api/messaging/extension_message_port.h
diff --git a/chrome/browser/extensions/api/messaging/extension_message_port.h b/chrome/browser/extensions/api/messaging/extension_message_port.h
index ccf9b69a9d85a4a2b28bb75d71481fdef2db114d..7cc386a07b5b55ecb1ebc8a907bba64a3b931a75 100644
--- a/chrome/browser/extensions/api/messaging/extension_message_port.h
+++ b/chrome/browser/extensions/api/messaging/extension_message_port.h
@@ -9,6 +9,10 @@
 
 class GURL;
 
+namespace base {
+class ListValue;
+}
+
 namespace content {
 class RenderProcessHost;
 }  // namespace content
@@ -30,7 +34,7 @@ class ExtensionMessagePort : public MessageService::MessagePort {
       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;