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 613 matching lines @@
       </message>
       <message name="IDS_MESSAGE_CENTER_SETTINGS_DESCRIPTION_MULTIUSER" desc="The label to describe the settings dialog if there is more than one user.">
         Allow notifications from the following for each user:
       </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_NOTIFICATION_HEADER_DIVIDER_SYMBOL_WITH_SPACES" desc="The divider symbol between different parts of the notification header including spaces." translateable="false">

[fukino, 2017/06/22 08:57:43]

translatable?

[tetsui, 2017/06/23 02:33:04]

Removed. FYI: even though translateable seems misspelling, it's correct in
grit... https://cs.chromium.org/search/?q=translateable+grd&type=cs

+        ''' • '''

[fukino, 2017/06/22 08:57:43]

I'm not sure if we can expect that all fonts we use have a glyph for •.
Maybe we should use an image for this separator?

[yoshiki, 2017/06/22 13:27:37]

Android uses character, so IMO this character is ok.
https://android.googlesource.com/platform/frameworks/base/+/master/core/res/r...

I think it's better to have it as a constant in source code. like:

base::char16 kNotificationHeaderDividerSymbol = 0x2022;

[tetsui, 2017/06/23 02:33:04]

Done.

+      </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 76 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>