Add extension event histogram values for messaging, webRequest, and webview.

chrome/browser/extensions/api/messaging/message_service.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_MESSAGE_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_API_MESSAGING_MESSAGE_SERVICE_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 168 matching lines @@
   typedef std::map<int, PendingMessagesQueue> PendingChannelMap;
 
   // A map of channel ID to information about the extension that is waiting
   // for that channel to open. Used for lazy background pages.
   typedef std::string ExtensionID;
   typedef std::pair<content::BrowserContext*, ExtensionID>
       PendingLazyBackgroundPageChannel;
   typedef std::map<int, PendingLazyBackgroundPageChannel>
       PendingLazyBackgroundPageChannelMap;
 
-  // Common among OpenChannel* variants.
-  void OpenChannelImpl(scoped_ptr<OpenChannelParams> params);
+  // Common implementation for opening a channel configured by |params|.
+  // |did_enqueue| will be true if the channel opening was delayed while
+  // waiting for an event page to start, false otherwise.
+  void OpenChannelImpl(content::BrowserContext* browser_context,
+                       scoped_ptr<OpenChannelParams> params,
+                       bool did_enqueue);
 
   void CloseChannelImpl(MessageChannelMap::iterator channel_iter,
                         int port_id,
                         const std::string& error_message,
                         bool notify_other_port);
 
   // Have MessageService take ownership of |channel|, and remove any pending
   // channels with the same id.
   void AddChannel(MessageChannel* channel, int receiver_port_id);
 
@@ skipping 88 matching lines @@
   LazyBackgroundTaskQueue* lazy_background_task_queue_;
 
   base::WeakPtrFactory<MessageService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageService);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_MESSAGING_MESSAGE_SERVICE_H_