[NTP4] Track the position of each app that's launched.

chrome/browser/resources/ntp4/tile_page.js

 // Copyright (c) 2012 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('ntp4', function() {
   'use strict';
 
   // We can't pass the currently dragging tile via dataTransfer because of
   // http://crbug.com/31037
   var currentlyDraggingTile = null;
@@ skipping 452 matching lines @@
     },
 
     get tiles() {
       return this.tileElements_;
     },
 
     get tileCount() {
       return this.tileElements_.length;
     },
 
+    get tileGrid() {
+      return this.tileGrid_;
+    },
+
     get selected() {
       return Array.prototype.indexOf.call(this.parentNode.children, this) ==
           ntp4.getCardSlider().currentCard;
     },
 
+    get layoutValues() {
+      return this.layoutValues_;
+    },
+
     /**
      * The size of the margin (unused space) on the sides of the tile grid, in
      * pixels.
      * @type {number}
      */
     get sideMargin() {
       return this.layoutValues_.leftMargin;
     },
 
     /**
@@ skipping 801 matching lines @@
       assert(false);
     },
   };
 
   return {
     getCurrentlyDraggingTile: getCurrentlyDraggingTile,
     setCurrentDropEffect: setCurrentDropEffect,
     TilePage: TilePage,
   };
 });