MD Settings: About page, implementing detailed build info.

chrome/browser/resources/settings/about_page/detailed_build_info.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 'settings-detailed-build-info' contains detailed build
+ * information for ChromeOS.
+ */
+
+(function() {
+
+/**
+ * @param {!BrowserChannel} channel
+ * @return {string}
+ */
+function browserChannelToI18nId(channel) {

[tommycli, 2016/05/13 18:24:26]

I would suggest if it's only used once, to just inline it. Then you could also
get rid of the (function() { business

[dpapad, 2016/05/13 19:28:02]

Thought about this. If I inline it then I can no longer use the
assertNotReached(), or I have to inline but still keep it as a function (as
follows), 

browserProxy.getCurrentChannel().then(function(channel) {
  var browserChannelToI18nId = function(...) {
    ...
    assertNotReached();
  };
 
  this.currentlyOnChannelText_ = this.i18n(
     'aboutCurrentlyOnChannel',
      this.i18n(browserChannelToI18nId(channel)));
}.bind(this));

Decided to keep it as is instead, which also makes the ready() method shorter
and slightly more readable.

+  switch (channel) {
+    case BrowserChannel.BETA: return 'aboutChannelBeta';
+    case BrowserChannel.DEV: return 'aboutChannelDev';
+    case BrowserChannel.STABLE: return 'aboutChannelStable';
+  }
+
+  assertNotReached();
+}
+
+Polymer({
+  is: 'settings-detailed-build-info',
+
+  behaviors: [I18nBehavior],
+
+  properties: {
+    /** @private {!VersionInfo} */
+    versionInfo_: Object,
+
+    /** @private */
+    currentlyOnChannelText_: String,
+  },
+
+  /** @override */
+  ready: function() {
+    var browserProxy = settings.AboutPageBrowserProxyImpl.getInstance();
+    browserProxy.refreshUpdateStatus();
+
+    browserProxy.getVersionInfo().then(function(versionInfo) {
+      this.versionInfo_ = versionInfo;
+    }.bind(this));
+    browserProxy.getCurrentChannel().then(function(channel) {
+      this.currentlyOnChannelText_ = this.i18n(
+          'aboutCurrentlyOnChannel',
+          this.i18n(browserChannelToI18nId(channel)));
+    }.bind(this));
+  },
+
+  /**
+   * @param {string} version
+   * @return {boolean}
+   * @private
+   */
+  shouldShowVersion_: function(version) {
+    return version.length > 0;
+  },
+});
+
+})();