Don't request missing favicon on every page request.

chrome/browser/notifications/message_center_notification_manager.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_NOTIFICATIONS_MESSAGE_CENTER_NOTIFICATION_MANAGER_H_
 #define CHROME_BROWSER_NOTIFICATIONS_MESSAGE_CENTER_NOTIFICATION_MANAGER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 73 matching lines @@
                                 int size,
                                 const SetImageCallback& callback);
     void StartDownloadByKey(const Notification& notification,
                             const char* key,
                             int size,
                             const SetImageCallback& callback);
 
     // FaviconHelper callback.
     void DownloadComplete(const SetImageCallback& callback,
                           int download_id,
+                          int http_status_code,
                           const GURL& image_url,
                           int requested_size,
                           const std::vector<SkBitmap>& bitmaps);
    private:
     // Used to keep track of the number of pending downloads.  Once this
     // reaches zero, we can tell the delegate that we don't need the
     // RenderViewHost anymore.
     void AddPendingDownload();
     void PendingDownloadCompleted();
 
@@ skipping 65 matching lines @@
                                  bool by_user);
 
   // Returns the ProfileNotification for the |id|, or NULL if no such
   // notification is found.
   ProfileNotification* FindProfileNotification(const std::string& id) const;
 
   DISALLOW_COPY_AND_ASSIGN(MessageCenterNotificationManager);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_MESSAGE_CENTER_NOTIFICATION_MANAGER_H_