MD Settings/About: Implement update progress percentage

chrome/browser/resources/settings/about_page/about_page.js

Index: chrome/browser/resources/settings/about_page/about_page.js
diff --git a/chrome/browser/resources/settings/about_page/about_page.js b/chrome/browser/resources/settings/about_page/about_page.js
index cdf419a16127abacf240781862a792db44cce77d..520e4acf59ac509ce89cf1a7ed3dcd433b14faca 100644
--- a/chrome/browser/resources/settings/about_page/about_page.js
+++ b/chrome/browser/resources/settings/about_page/about_page.js
@@ -166,7 +166,9 @@ Polymer({
               this.i18n(settings.browserChannelToI18nId(this.targetChannel_)));

[hcarmona, 2016/09/09 21:51:52]

Does changing the channel also need a progress percentage?

[Dan Beam, 2016/09/10 00:56:02]

Done. (thanks!)

         }
 </if>
-        return this.i18n('aboutUpgradeUpdating');
+        assert(typeof this.currentUpdateStatusEvent_.progress == 'number');
+        return this.i18n('aboutUpgradeUpdating',
+                         this.currentUpdateStatusEvent_.progress + '%');
       default:
         var message = this.currentUpdateStatusEvent_.message;
         return message ?