Moving where I'm doing dropEffect normalization.

chrome/browser/resources/ntp4/nav_dot.js

 // Copyright (c) 2011 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.
 
 /**
  * @fileoverview Nav dot
  * This is the class for the navigation controls that appear along the bottom
  * of the NTP.
  */
 
@@ skipping 185 matching lines @@
      * A dragged element has moved over the navigation dot. Show the correct
      * indicator and prevent default handling so the <input> won't act as a drag
      * target.
      * @param {Event} e The MouseOver event for the drag.
      * @private
      */
     doDragOver: function(e) {
       e.preventDefault();
 
       if (!this.dragWrapper_.isCurrentDragTarget)
-        e.dataTransfer.dropEffect = 'none';
+        ntp4.setCurrentDropEffect(e.dataTransfer, 'none');
       else
         this.page_.setDropEffect(e.dataTransfer);
     },
 
     /**
      * A dragged element has been dropped on the navigation dot. Tell the page
      * to append it.
      * @param {Event} e The MouseOver event for the drag.
      * @private
      */
@@ skipping 35 matching lines @@
     onTransitionEnd_: function(e) {
       if (e.propertyName === 'max-width' && this.classList.contains('small'))
         this.parentNode.removeChild(this);
     },
   };
 
   return {
     NavDot: NavDot,
   };
 });