[MD Bookmarks] Refactor window timer mocking.

chrome/test/data/webui/md_bookmarks/dnd_manager_test.js

 // Copyright 2017 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.
 
 suite('drag and drop', function() {
   var app;
   var list;
   var rootFolderNode;
   var store;
   var dndManager;
@@ skipping 83 matching lines @@
     draggedIds = null;
     chrome.bookmarkManagerPrivate.startDrag = function(nodes, isTouch) {
       draggedIds = nodes;
     };
 
     app = document.createElement('bookmarks-app');
     replaceBody(app);
     list = app.$$('bookmarks-list');
     rootFolderNode = app.$$('bookmarks-folder-node');
     dndManager = app.dndManager_;
-    dndManager.disableTimeoutsForTesting();
+    dndManager.setTimerProxyForTesting(new bookmarks.TestTimerProxy());
     Polymer.dom.flush();
   });
 
   test('dragInfo isDraggingFolderToDescendant', function() {
     var dragInfo = new bookmarks.DragInfo();
     var nodes = store.data.nodes;
     dragInfo.handleChromeDragEnter(createDragData(['11']));
     assertTrue(dragInfo.isDraggingFolderToDescendant('111', nodes));
     assertFalse(dragInfo.isDraggingFolderToDescendant('1', nodes));
     assertFalse(dragInfo.isDraggingFolderToDescendant('2', nodes));
@@ skipping 406 matching lines @@
     var dragElement = getListItem('12');
     dispatchDragEvent('dragstart', dragElement);
 
     // Can't drag onto the unmodifiable node.
     var dragTarget = getFolderNode('2');
     dispatchDragEvent('dragover', dragTarget);
     assertEquals(
         DropPosition.NONE, dndManager.calculateValidDropPositions_(dragTarget));
   });
 });