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

chrome/test/data/webui/extensions/extension_detail_view_test.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 Suite of tests for extensions-detail-view. */
 cr.define('extension_detail_view_tests', function() {
   /** @enum {string} */
   var TestNames = {
     Layout: 'layout',
     ClickableElements: 'clickable elements',
@@ skipping 36 matching lines @@
         document.body.appendChild(item);
       });
 
       test(assert(TestNames.Layout), function() {
         Polymer.dom.flush();
 
         extension_test_util.testIronIcons(item);
 
         var testIsVisible = extension_test_util.isVisible.bind(null, item);
         expectTrue(testIsVisible('#close-button'));
-        expectTrue(testIsVisible('#open-in-webstore'));
+        expectFalse(testIsVisible('#open-homepage'));
         expectFalse(testIsVisible('#options'));
 
         // Check the checkboxes visibility and state. They should be visible
         // only if the associated option is enabled, and checked if the
         // associated option is active.
         var accessOptions = [
           {key: 'incognitoAccess', id: '#allow-incognito'},
           {key: 'fileAccess', id: '#allow-on-file-urls'},
           {key: 'runOnAllUrls', id: '#allow-on-all-sites'},
           {key: 'errorCollection', id: '#collect-errors'},
@@ skipping 33 matching lines @@
         expectTrue(testIsVisible('#permissions-list'));
         expectEquals(2,
                      item.$$('#permissions-list').querySelectorAll('li').
                          length);
         expectFalse(testIsVisible('#no-permissions'));
 
         var optionsUrl =
              'chrome-extension://' + extensionData.id + '/options.html';
         item.set('data.optionsPage', {openInTab: true, url: optionsUrl});
         expectTrue(testIsVisible('#options'));
+
+        var homepageUrl = 'https://www.example.com/';
+        item.set('data.homePage', {specified: true, url: homepageUrl});
+        expectTrue(testIsVisible('#open-homepage'));
+        expectEquals(homepageUrl, item.$$('#open-homepage').href);
       });
 
       test(assert(TestNames.ClickableElements), function() {
         var optionsUrl =
             'chrome-extension://' + extensionData.id + '/options.html';
         item.set('data.optionsPage', {openInTab: true, url: optionsUrl});
         Polymer.dom.flush();
         mockDelegate.testClickingCalls(
             item.$$('#allow-incognito'), 'setItemAllowedIncognito',
             [extensionData.id, true]);
@@ skipping 10 matching lines @@
             item.$$('#options'), 'showItemOptionsPage', [extensionData.id]);
       });
     });
   }
 
   return {
     registerTests: registerTests,
     TestNames: TestNames,
   };
 });