Enrich fileBrowserPrivate.onFileTransfersUpdated event to support displaying total number of jobs.

chrome/browser/chromeos/extensions/file_manager/event_router.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_CHROMEOS_EXTENSIONS_FILE_MANAGER_EVENT_ROUTER_H_
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_EVENT_ROUTER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 146 matching lines @@
       extensions::api::file_browser_private::MountCompletedEventType event_type,
       chromeos::MountError error,
       const VolumeInfo& volume_info);
 
   // If needed, opens a file manager window for the removable device mounted at
   // |mount_path|. Disk.mount_path() is empty, since it is being filled out
   // after calling notifying observers by DiskMountManager.
   void ShowRemovableDeviceInFileManager(VolumeType type,
                                         const base::FilePath& mount_path);
 
-  // Sends onFileTranferUpdated to extensions if needed. If |always| is true,
-  // it sends the event always. Otherwise, it sends the event if enough time has
-  // passed from the previous event so as not to make extension busy.
-  void SendDriveFileTransferEvent(bool always);
-
   // Manages the list of currently active Drive file transfer jobs.
   struct DriveJobInfoWithStatus {
     DriveJobInfoWithStatus();
     DriveJobInfoWithStatus(const drive::JobInfo& info,
                            const std::string& status);
     drive::JobInfo job_info;
     std::string status;
   };
+
+  // Sends onFileTransferUpdate event right now if |immediate| is set. Otherwise
+  // it refrains from sending for a short while, and after that it sends the
+  // most recently scheduled event once.
+  // The delay is for waiting subsequent 'added' events to come after the first
+  // one when multiple tasks are added. This way, we can avoid frequent UI
+  // update caused by differences between singular and plural cases.
+  void ScheduleDriveFileTransferEvent(const drive::JobInfo& job_info,
+                                      const std::string& status,
+                                      bool immediate);
+
+  // Sends the most recently scheduled onFileTransferUpdated event to
+  // extensions.
+  // This is used for implementing ScheduledDriveFileTransferEvent().
+  void SendDriveFileTransferEvent();
+
   std::map<drive::JobID, DriveJobInfoWithStatus> drive_jobs_;
-  base::Time last_file_transfer_event_;
+  scoped_ptr<DriveJobInfoWithStatus> drive_job_info_for_scheduled_event_;
   base::Time last_copy_progress_event_;
+  base::Time next_send_file_transfer_event_;
 
   WatcherMap file_watchers_;
   scoped_ptr<PrefChangeRegistrar> pref_change_registrar_;
   Profile* profile_;
 
   scoped_ptr<DeviceEventRouter> device_event_router_;
 
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate the weak pointers before any other members are destroyed.
   base::WeakPtrFactory<EventRouter> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(EventRouter);
 };
 
 }  // namespace file_manager
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_EVENT_ROUTER_H_