[MD Extensions] Add logic for opening the extension's home page

chrome/browser/resources/md_extensions/detail_view.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.
 
 cr.define('extensions', function() {
   'use strict';
 
   var DetailView = Polymer({
     is: 'extensions-detail-view',
 
@@ skipping 34 matching lines @@
      * @private
      */
     hasPermissions_: function() {
       return this.data.permissions.length > 0;
     },
 
     /**
      * @return {boolean}
      * @private
      */
+    shouldShowHomepageButton_: function() {
+      // Note: we ignore |data.homePage.specified| - we use an extension's
+      // webstore entry as a homepage if the extension didn't explicitly specify
+      // a homepage. (|url| can still be unset in the case of unpacked
+      // extensions.)
+      return this.data.homePage.url.length > 0;
+    },
+
+    /**
+     * @return {boolean}
+     * @private
+     */
     shouldShowOptionsButton_: function() {
       return !!this.data.optionsPage;
     },
 
     /**
      * @return {boolean}
      * @private
      */
     shouldShowOptionsSection_: function() {
       return this.data.incognitoAccess.isEnabled ||
@@ skipping 41 matching lines @@
 
     /** @private */
     computeSourceString_: function() {
       return extensions.getItemSourceString(
           extensions.getItemSource(this.data));
     }
   });
 
   return {DetailView: DetailView};
 });