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

chrome/browser/resources/ntp4/tile_page.js

Index: chrome/browser/resources/ntp4/tile_page.js
diff --git a/chrome/browser/resources/ntp4/tile_page.js b/chrome/browser/resources/ntp4/tile_page.js
index 11907ffc0764741d560911dbf4de49d2b2687ab4..b242da48c54198780b83461fe66032d5090d10f1 100644
--- a/chrome/browser/resources/ntp4/tile_page.js
+++ b/chrome/browser/resources/ntp4/tile_page.js
@@ -470,11 +470,19 @@ cr.define('ntp4', function() {
       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.