MD Settings: About page, hooking up channel switcher dialog.

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.
  */
 
 Polymer({
   is: 'settings-detailed-build-info',
 
   behaviors: [I18nBehavior],
 
   properties: {
     /** @private {!VersionInfo} */
     versionInfo_: Object,
 
     /** @private */
     currentlyOnChannelText_: String,
+
+    /** @private */
+    showChannelSwitcherDialog_: Boolean,
+
+    /** @private */
+    canChangeChannel_: {
+      type: Boolean,
+      value: function() {
+        return loadTimeData.getBoolean('aboutCanChangeChannel');
+      },
+    },
   },
 
   /** @override */
   ready: function() {
     var browserProxy = settings.AboutPageBrowserProxyImpl.getInstance();
     browserProxy.pageReady();
 
     browserProxy.getVersionInfo().then(function(versionInfo) {
       this.versionInfo_ = versionInfo;
     }.bind(this));
     browserProxy.getCurrentChannel().then(function(channel) {
       this.currentlyOnChannelText_ = this.i18n(
           'aboutCurrentlyOnChannel',
           this.i18n(settings.browserChannelToI18nId(channel)));
     }.bind(this));
   },
 
   /**
    * @param {string} version
    * @return {boolean}
    * @private
    */
   shouldShowVersion_: function(version) {
     return version.length > 0;
   },
+
+  /** @private */
+  onChangeChannelTap_: function() {
+    this.showChannelSwitcherDialog_ = true;
+    this.async(function() {

[dschuyler, 2016/05/27 22:16:21]

Please add a comment above this.async to
explain why we need to wait.  Maybe:
// Async to wait for dialog to appear in the dom.

[dpapad, 2016/05/27 23:32:18]

Done.

+      var dialog = this.$$('settings-channel-switcher-dialog');
+      // Register listener to detect when the dialog is closed. Flip the boolean
+      // once closed to force a restamp next time it is shown such that the
+      // previous dialog's contents are cleared.
+      dialog.addEventListener('iron-overlay-closed', function() {
+        this.showChannelSwitcherDialog_ = false;
+      }.bind(this));
+    }.bind(this));
+  },
 });