Make update over cellular an option for user

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview A helper object used from the "About" section to interact with
  * the browser.
  */
 
 // <if expr="chromeos">
@@ skipping 40 matching lines @@
  * @enum {string}
  */
 var UpdateStatus = {
   CHECKING: 'checking',
   UPDATING: 'updating',
   NEARLY_UPDATED: 'nearly_updated',
   UPDATED: 'updated',
   FAILED: 'failed',
   DISABLED: 'disabled',
   DISABLED_BY_ADMIN: 'disabled_by_admin',
+  NEED_PERMISSION_TO_UPDATE: 'need_permission_to_update',
 };
 
 // <if expr="_google_chrome and is_macosx">
 /**
  * @typedef {{
  *   hidden: boolean,
  *   disabled: boolean,
  *   actionable: boolean,
  *   text: (string|undefined)
  * }}
@@ skipping 135 matching lines @@
       chrome.send('openFeedbackDialog');
     },
 // </if>
 
 // <if expr="chromeos">
     /** @override */
     requestUpdate: function() {
       chrome.send('requestUpdate');
     },
 
+    requestUpdateOverCellular: function(target_version, target_size) {
+      chrome.send('requestUpdateOverCellular', [target_version, target_size]);
+    },

[stevenjb, 2017/05/10 23:29:05]

This should also be defined (and documented) in the prototype and marked /**
@override */ here. I'm confused why we would need to pass |target_size| here.

[weidongg, 2017/05/11 16:34:05]

I discussed with @adlr, he says
"Technically version should be enough, but there are a few scenarios where it
could try to get a delta (small) update and then fail a few times and then go
for a full update (big), which would use more data than the user agreed to.
Also, it's unlikely, but a server change could remove the delta update and leave
the full one which would be the same issue."

[stevenjb, 2017/05/11 17:20:15]

I'm still confused. It looks like we are just passing the 'size' parameter from
the 'updateStatusChaged' event back to requestUdpateOverCellular? Do we
anticipate the UI ever changing either the size or version information? It seems
like this doesn't actually need any parameters and the model (the C++ code)
should just retrieve those values?

+
     /** @override */
     setChannel: function(channel, isPowerwashAllowed) {
       chrome.send('setChannel', [channel, isPowerwashAllowed]);
     },
 
     /** @override */
     getChannelInfo: function() {
       return cr.sendWithPromise('getChannelInfo');
     },
 
     /** @override */
     getVersionInfo: function() {
       return cr.sendWithPromise('getVersionInfo');
     },
 
     /** @override */
     getRegulatoryInfo: function() {
       return cr.sendWithPromise('getRegulatoryInfo');
     }
 // </if>
   };
 
   return {
     AboutPageBrowserProxy: AboutPageBrowserProxy,
     AboutPageBrowserProxyImpl: AboutPageBrowserProxyImpl,
     browserChannelToI18nId: browserChannelToI18nId,
     isTargetChannelMoreStable: isTargetChannelMoreStable,
   };
 });