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

chrome/browser/chromeos/extensions/file_manager/event_router.h

Index: chrome/browser/chromeos/extensions/file_manager/event_router.h
diff --git a/chrome/browser/chromeos/extensions/file_manager/event_router.h b/chrome/browser/chromeos/extensions/file_manager/event_router.h
index 7d187ea30097696c0b47b7b46c41a38e52d18dc8..2063597c02500a7f74fae90cd0d0c7f5c6aaeea8 100644
--- a/chrome/browser/chromeos/extensions/file_manager/event_router.h
+++ b/chrome/browser/chromeos/extensions/file_manager/event_router.h
@@ -164,11 +164,6 @@ class EventRouter : public chromeos::NetworkStateHandlerObserver,
   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();
@@ -177,9 +172,23 @@ class EventRouter : public chromeos::NetworkStateHandlerObserver,
     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_;