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;
   };
+
+  // Schedule onFileTransferUpdated event to count following events.

[kinaba, 2014/09/03 15:54:19]

"to count following events" is still vague.
I guess it can be clearer if first "what it does" is explained, and then "why".

How about this:

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.

[iseki, 2014/09/04 00:50:07]

Done.

+  // If only one event receive, Files.app display the name of a item otherwise
+  // display the number of items. Counting the event is necessary to avoid
+  // displaying the name of a item.
+  void ScheduleDriveFileTransferEvent(const drive::JobInfo& job_info,
+                                      const std::string& status,
+                                      bool immediate);
+
+  // Sends onFileTranferUpdated to extensions if call time is after
+  // nextSendTime_.
+  void SendDriveFileTransferEvent();

[kinaba, 2014/09/03 15:54:19]

This method itself does not refer timing anymore, so the comment is not quite
adequate.

How about:

Sends the most recently scheduled onFileTransferUpdated event to extensions.
This is used for implementing ScheduledDriveFileTransferEvent().

[iseki, 2014/09/04 00:50:07]

Done.

+
   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_