MD Settings/About: Implement update progress percentage

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- About Page -->
   <if expr="chromeos">
     <message name="IDS_SETTINGS_ABOUT_PAGE_DETAILED_BUILD_INFO" desc="Label describing the section that shows detailed information about the current Chrome build.">
       Detailed build information
     </message>
     <message name="IDS_SETTINGS_ABOUT_PAGE_ARC_VERSION" desc="Label for ARC version">
       ARC Version
@@ skipping 22 matching lines @@
     <message name="IDS_SETTINGS_ABOUT_PAGE_PLATFORM" desc="Label for Platform">
       Platform
     </message>
     <message name="IDS_SETTINGS_ABOUT_PAGE_RELAUNCH" desc="The label for the relaunch button that relaunches the browser once update is complete">
       Restart
     </message>
     <message name="IDS_SETTINGS_ABOUT_PAGE_RELAUNCH_AND_POWERWASH" desc="The label for the  button that relaunches and powerwashes the browser once update is complete">
       Relaunch and Powerwash
     </message>
     <message name="IDS_SETTINGS_UPGRADE_UPDATING" desc="Status label: Updating ChromiumOS or ChromeOS">
-      Updating your device
+      Updating your device (<ph name="PROGRESS_PERCENT">$1<ex>90%</ex></ph>)
     </message>
     <message name="IDS_SETTINGS_UPGRADE_SUCCESSFUL_RELAUNCH" desc="Status label: Successfully updated ChromiumOS/ChromeOS">
       Nearly up to date! Restart your device to finish updating.
     </message>
     <message name="IDS_SETTINGS_UPGRADE_UPDATING_CHANNEL_SWITCH" desc="Status label: Updating ChromiumOS/ChromeOS to a specified channel">
-      Updating your device to <ph name="CHANNEL_NAME">$1<ex>stable</ex></ph> channel
+      Updating your device to <ph name="CHANNEL_NAME">$1<ex>stable</ex></ph> channel (<ph name="PROGRESS_PERCENT">$2<ex>90%</ex></ph>)
     </message>
     <message name="IDS_SETTINGS_UPGRADE_SUCCESSFUL_CHANNEL_SWITCH" desc="Status label: Channel was successfully switched on ChromiumOS/ChromeOS">
       Channel changed. Restart your device to apply changes.
     </message>
     <message name="IDS_SETTINGS_UPGRADE_UP_TO_DATE" desc="Status label: Already up to date (ChromiumOS/ChromeOS)">
       Your <ph name="DEVICE_TYPE">$1<ex>Chromebook</ex></ph> is up to date.
     </message>
 
     <!-- About Page: Channel switcher dialog -->
     <message name="IDS_SETTINGS_ABOUT_PAGE_CHANGE_CHANNEL" desc="Button label for channel switch.">
@@ skipping 2230 matching lines @@
       System
     </message>
     <message name="IDS_SETTINGS_SYSTEM_HARDWARE_ACCELERATION_LABEL" desc="Label for the checkbox that forces Chrome to render via hardware acceleration (GPU) when available.">
       Use hardware acceleration when available
     </message>
     <message name="IDS_SETTINGS_SYSTEM_PROXY_SETTINGS_BUTTON" desc="Text for the button that changes a user's network proxy settings.">
       Change proxy settings
     </message>
   </if>
 </grit-part>