MD Downloads: improve early loading shim

chrome/browser/resources/md_downloads/manager.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('downloads', function() {
   var Manager = Polymer({
     is: 'downloads-manager',
 
     properties: {
       /** @private */
@@ skipping 22 matching lines @@
       },
 
       /** @private */
       spinnerActive_: {
         type: Boolean,
         notify: true,
       },
     },
 
     hostAttributes: {
+      // TODO(dbeam): this should use a class instead.
       loading: true,
     },
 
     listeners: {
       'downloads-list.scroll': 'onListScroll_',
       'toolbar.search-changed': 'onSearchChanged_',
     },
 
     observers: [
       'itemsChanged_(items_.*)',
     ],
 
+    attached: function() {
+      document.documentElement.classList.remove('loading');
+    },
+
     /** @private {!PromiseResolver} */
     loaded_: new PromiseResolver,
 
     /** @private */
     clearAll_: function() {
       this.set('items_', []);
     },
 
     /** @private */
     hasDownloadsChanged_: function() {
@@ skipping 166 matching lines @@
   Manager.removeItem = function(index) {
     Manager.get().removeItem_(index);
   };
 
   Manager.updateItem = function(index, data) {
     Manager.get().updateItem_(index, data);
   };
 
   return {Manager: Manager};
 });