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

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="chromeos">. -->
 <grit-part>
   <message name="IDS_EMPTY_STRING" desc="Empty string, exist only to make code generic. No translation required.">
   </message>
   <message name="IDS_CHROMEBOOK" desc="The localized name for Chromebook.">
     Chromebook
   </message>
   <message name="IDS_CHROMEBOX" desc="The localized name for Chromebox">
@@ skipping 482 matching lines @@
   </message>
   <message name="IDS_FILE_BROWSER_ZIP_FILESYSTEM_ERROR" desc="File Manager error message.">
     Zipping failed. <ph name="ERROR_MESSAGE">$1<ex>An error occurred (code: ABORT)</ex></ph>
   </message>
   <message name="IDS_FILE_BROWSER_ZIP_UNEXPECTED_ERROR" desc="File Manager error message.">
     Zipping failed, unexpected error: $1
   </message>
   <message name="IDS_FILE_BROWSER_SYNC_FILE_NAME" desc="File Manager status message.">
     Syncing <ph name="FILE_NAME">$1<ex>movie.avi</ex></ph>...
   </message>
+  <message name="IDS_FILE_BROWSER_SYNC_FILE_NUMBER" desc="File Manager status message.">
+    Syncing <ph name="NUMBER_OF_FILES">$1<ex>7</ex></ph> items...
+  </message>
   <message name="IDS_FILE_BROWSER_SYNC_DELETE_WITHOUT_PERMISSION_ERROR" desc="File Manager status message shown when the drive sync is failed because a user try to remove shared files that the user does not own.">
     "<ph name="FILENAME">$1<ex>photo.jpg</ex></ph>" has been shared with you. You cannot delete it because you do not own it.
   </message>
   <message name="IDS_FILE_BROWSER_SYNC_SERVICE_UNAVAILABLE_ERROR" desc="File Manager status message shown when the drive sync is failed because Google Drive is temporary unavailable.">
     Google Drive is not available right now. Uploading will automatically restart once Google Drive is back.
   </message>
   <message name="IDS_FILE_BROWSER_SYNC_MISC_ERROR" desc="File Manager status message shown when the drive sync is failed because of miscellaneous errors.">
     Google Drive was unable to sync "<ph name="FILENAME">$1<ex>photo.jpg</ex></ph>" right now. Please try again later.
   </message>
   <message name="IDS_FILE_BROWSER_SHARE_ERROR" desc="File Manager error message when sharing a file or a directory on Drive fails because of internet connection problems.">
@@ skipping 5294 matching lines @@
   <message name="IDS_SET_TIME_BUTTON_CLOSE" desc="Text for the button to close the window.">
     Done
   </message>
   <message name="IDS_SET_TIME_DATE_LABEL" desc="Label for the date input element.">
     System date
   </message>
   <message name="IDS_SET_TIME_TIME_LABEL" desc="Label for the time input element.">
     System time
   </message>
 </grit-part>