Add percentage of progress in notification header.

ui/strings/ui_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- This file contains definitions of resources that will be translated for
 each locale. Specifically, these are UI strings that are used by app/ that
 need to be translated for each locale.-->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       output_all_resource_defines="false" source_lang_id="en" enc_check="möl">
   <outputs>
     <!-- TODO add each of your output files.  Modify the three below, and add
@@ skipping 616 matching lines @@
       </message>
       <message name="IDS_MESSAGE_CENTER_SETTINGS" desc="The menu entry or button for visiting the appropriate settings page.">
         Settings...
       </message>
       <message name="IDS_MESSAGE_CENTER_CLEAR_ALL" desc="The button for clearing all notifications.">
         Clear All
       </message>
       <message name="IDS_MESSAGE_CENTER_LIST_NOTIFICATION_OVERFLOW_INDICATOR" desc="The overflow indicator shown when a list notification has more list items than visible ones. Should be same as AndroidPlatform msgId 1863231301642314183. (frameworks/base/packages/SystemUI/res/values/strings.xml:notification_group_overflow_indicator)">
         + <ph name="NUMBER">$1<ex>3</ex></ph>
       </message>
+      <message name="IDS_MESSAGE_CENTER_NOTIFICATION_PROGRESS_PERCENTAGE" desc="The summary text in a notification that is shown with progress bar.">
+        <ph name="NUMBER">$1<ex>75</ex></ph> %
+      </message>
       <if expr="not use_titlecase">
         <message name="IDS_MESSAGE_CENTER_QUIET_MODE_BUTTON_TOOLTIP" desc="The tooltip text for the do not disturb button.">
           Do not disturb
         </message>
       </if>
       <if expr="use_titlecase">
         <message name="IDS_MESSAGE_CENTER_QUIET_MODE_BUTTON_TOOLTIP" desc="In Title Case: The tooltip text for the do not disturb button.">
           Do Not Disturb
         </message>
       </if>
@@ skipping 82 matching lines @@
       <!-- Display names -->
       <message name="IDS_DISPLAY_NAME_UNKNOWN" desc="The name used for a display whose name is unknown, which is shown in the display settings and ash tray.">
         Unknown Display
       </message>
       <message name="IDS_DISPLAY_NAME_INTERNAL" desc="The name used for internal displays, which is shown in the display settings.">
         Internal Display
       </message>
     </messages>
   </release>
 </grit>