remove ntp app install hint

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('ntp', function() {
   'use strict';
 
   // We can't pass the currently dragging tile via dataTransfer because of
   // http://crbug.com/31037
   var currentlyDraggingTile = null;
@@ skipping 966 matching lines @@
       this.tileGrid_.style.WebkitMaskBoxImage = gradient;
     },
 
     updateTopMargin_: function() {
       var layout = this.layoutValues_;
 
       // The top margin is set so that the vertical midpoint of the grid will
       // be 1/3 down the page.
       var numTiles = this.tileCount +
           (this.isCurrentDragTarget && !this.withinPageDrag_ ? 1 : 0);
-      // Minimum of 1 row (this can come into play when there is an app install
-      // hint hiding the webstore tile, and there are no other tiles).
       var numRows = Math.max(1, Math.ceil(numTiles / layout.numRowTiles));
       var usedHeight = layout.rowHeight * numRows;
       var newMargin = document.documentElement.clientHeight / 3 -
           usedHeight / 3 - this.contentPadding;
       // The 'height' style attribute of topMargin is non-zero to work around
       // webkit's collapsing margin behavior, so we have to factor that into
       // our calculations here.
       newMargin = Math.max(newMargin, 0) - this.topMargin_.offsetHeight;
 
       // |newMargin| is the final margin we actually want to show. However,
@@ skipping 340 matching lines @@
       assert(false);
     },
   };
 
   return {
     getCurrentlyDraggingTile: getCurrentlyDraggingTile,
     setCurrentDropEffect: setCurrentDropEffect,
     TilePage: TilePage,
   };
 });