Kill NewTabPage.NumberOfMouseOvers.

chrome/browser/resources/local_ntp/most_visited_single.js

 /* Copyright 2015 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. */
 
  // Single iframe for NTP tiles.
 (function() {
 'use strict';
 
 
 /**
@@ skipping 21 matching lines @@
   // Unused here.
   NTP_EXTERNAL_TILE: 5,
   // There was an error in loading both the thumbnail image and the fallback
   // (if it was provided), resulting in a gray tile.
   NTP_THUMBNAIL_ERROR: 6,
   // Used a gray tile with the domain as the fallback for a failed thumbnail.
   // Unused here.
   NTP_GRAY_TILE_FALLBACK: 7,
   // The visuals of that tile's fallback are handled externally. Unused here.
   NTP_EXTERNAL_TILE_FALLBACK: 8,
-  // The user moused over an NTP tile.
-  NTP_MOUSEOVER: 9,

[Marc Treib, 2016/07/05 08:07:31]

Hm, there's a few other ones here that say "unused here". Could you remove the
others too, or comment them all out?

[sfiera, 2016/07/05 18:24:40]

Done.

   // A NTP Tile has finished loading (successfully or failing).
   NTP_TILE_LOADED: 10,
 };
 
 
 /**
  * Total number of tiles to show at any time. If the host page doesn't send
  * enough tiles, we fill them blank.
  * @const {number}
  */
@@ skipping 406 matching lines @@
         if (inArrowDirection(this, nonEmptyTiles[i]) &&
             (!nextTile || inArrowDirection(nonEmptyTiles[i], nextTile))) {
           nextTile = nonEmptyTiles[i];
         }
       }
       if (nextTile) {
         nextTile.focus();
       }
     }
   });
-  // TODO(fserb): remove this or at least change to mouseenter.
-  tile.addEventListener('mouseover', function() {
-    logEvent(LOG_TYPE.NTP_MOUSEOVER);
-  });
 
   var title = tile.querySelector('.mv-title');
   title.innerText = data.title;
   title.style.direction = data.direction || 'ltr';
   if (NUM_TITLE_LINES > 1) {
     title.classList.add('multiline');
   }
 
   if (USE_ICONS) {
     var thumb = tile.querySelector('.mv-thumb');
@@ skipping 161 matching lines @@
     var html = document.querySelector('html');
     html.dir = 'rtl';
   }
 
   window.addEventListener('message', handlePostMessage);
 };
 
 
 window.addEventListener('DOMContentLoaded', init);
 })();