[MD Extensions] Add a details subpage, move to one list

chrome/browser/resources/md_extensions/item_list.js

 // Copyright 2015 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() {
   var ItemList = Polymer({
     is: 'extensions-item-list',
 
+    behaviors: [
+      Polymer.NeonAnimatableBehavior,
+      Polymer.IronResizableBehavior
+    ],
+
     properties: {
+      animationConfig: {
+        type: Object,
+        value: function() {
+          return {
+            exit: [{
+              name: 'hero-animation',
+              id: 'hero',
+              fromPage: this,
+            }],
+          };
+        },
+      },
+
       /** @type {Array<!chrome.developerPrivate.ExtensionInfo>} */
       items: Array,
 
       /** @type {extensions.ItemDelegate} */
       delegate: Object,
 
       header: String,
 
       inDevMode: {
         type: Boolean,
         value: false,
       },
 
       filter: String,
     },
 
     listeners: {
       'list.extension-item-size-changed': 'itemSizeChanged_',
+      'list.extension-item-show-details': 'showItemDetails_',
     },
 
     /**
      * Updates the size for a given item.
      * @param {CustomEvent} e
      * @private
      * @suppress {checkTypes} Closure doesn't know $.list is an IronList.
      */
     itemSizeChanged_: function(e) {
       this.$.list.updateSizeForItem(e.detail.item);
     },
 
     /**
+     * Called right before an item enters the detailed view.
+     * @param {CustomEvent} e
+     * @private
+     */
+    showItemDetails_: function(e) {
+      this.sharedElements = {hero: e.detail.element};
+    },
+
+    /**
      * Computes the list of items to be shown.
      * @param {Object} changeRecord The changeRecord for |items|.
      * @param {string} filter The updated filter string.
      * @return {Array<!chrome.developerPrivate.ExtensionInfo>}
      * @private
      */
     computeShownItems_: function(changeRecord, filter) {
       return this.items.filter(function(item) {
         return item.name.toLowerCase().includes(this.filter.toLowerCase());
       }, this);
     },
   });
 
   return {
     ItemList: ItemList,
   };
 });