Refactor extension event distribution to use Values instead of JSON strings.

chrome/browser/extensions/event_router_forwarder.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_EVENT_ROUTER_FORWARDER_H_
 #define CHROME_BROWSER_EXTENSIONS_EVENT_ROUTER_FORWARDER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
+#include "base/values.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/browser_thread.h"
 
 class GURL;
 
 namespace extensions {
 
 // This class forwards events to EventRouters.
 // The advantages of this class over direct usage of EventRouters are:
 // - this class is thread-safe, you can call the functions from UI and IO
 //   thread.
 // - the class can handle if a profile is deleted between the time of sending
 //   the event from the IO thread to the UI thread.
 // - this class can be used in contexts that are not governed by a profile, e.g.
 //   by system URLRequestContexts. In these cases the |restrict_to_profile|
 //   parameter remains NULL and events are broadcasted to all profiles.
 class EventRouterForwarder
     : public base::RefCountedThreadSafe<EventRouterForwarder> {
  public:
   EventRouterForwarder();
 
   // Calls
   //   DispatchEventToRenderers(event_name, event_args, profile, event_url)
   // on all (original) profiles' EventRouters.
   // May be called on any thread.
   void BroadcastEventToRenderers(const std::string& event_name,
-                                 const std::string& event_args,
+                                 scoped_ptr<base::ListValue> event_args,
                                  const GURL& event_url);
 
   // Calls
   //   DispatchEventToExtension(extension_id, event_name, event_args,
   //       profile, event_url)
   // on all (original) profiles' EventRouters.
   // May be called on any thread.
   void BroadcastEventToExtension(const std::string& extension_id,
                                  const std::string& event_name,
-                                 const std::string& event_args,
+                                 scoped_ptr<base::ListValue> event_args,
                                  const GURL& event_url);
 
   // Calls
   //   DispatchEventToRenderers(event_name, event_args,
   //       use_profile_to_restrict_events ? profile : NULL, event_url)
   // on |profile|'s EventRouter. May be called on any thread.
   void DispatchEventToRenderers(const std::string& event_name,
-                                const std::string& event_args,
+                                scoped_ptr<base::ListValue> event_args,
                                 void* profile,
                                 bool use_profile_to_restrict_events,
                                 const GURL& event_url);
 
   // Calls
   //   DispatchEventToExtension(extension_id, event_name, event_args,
   //       use_profile_to_restrict_events ? profile : NULL, event_url)
   // on |profile|'s EventRouter. May be called on any thread.
   void DispatchEventToExtension(const std::string& extension_id,
                                 const std::string& event_name,
-                                const std::string& event_args,
+                                scoped_ptr<base::ListValue> event_args,
                                 void* profile,
                                 bool use_profile_to_restrict_events,
                                 const GURL& event_url);
 
  protected:
   // Protected for testing.
   virtual ~EventRouterForwarder();
 
   // Helper function for {Broadcast,Dispatch}EventTo{Extension,Renderers}.
   // Virtual for testing.
   virtual void HandleEvent(const std::string& extension_id,
                            const std::string& event_name,
-                           const std::string& event_args,
+                           scoped_ptr<base::ListValue> event_args,
                            void* profile,
                            bool use_profile_to_restrict_events,
                            const GURL& event_url);
 
   // Calls DispatchEventToRenderers or DispatchEventToExtension (depending on
   // whether extension_id == "" or not) of |profile|'s EventRouter.
   // |profile| may never be NULL.
   // Virtual for testing.
   virtual void CallEventRouter(Profile* profile,
                                const std::string& extension_id,
                                const std::string& event_name,
-                               const std::string& event_args,
+                               scoped_ptr<base::ListValue> event_args,
                                Profile* restrict_to_profile,
                                const GURL& event_url);
 
  private:
   friend class base::RefCountedThreadSafe<EventRouterForwarder>;
 
   DISALLOW_COPY_AND_ASSIGN(EventRouterForwarder);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EVENT_ROUTER_FORWARDER_H_