Remove a bunch of broken/unused/non-useful NTP UMA histograms

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';
 
 
 /**
  * The different types of events that are logged from the NTP.  This enum is
  * used to transfer information from the NTP JavaScript to the renderer and is
  * not used as a UMA enum histogram's logged value.
  * Note: Keep in sync with common/ntp_logging_events.h
  * @enum {number}
  * @const
  */
 var LOG_TYPE = {
   // The suggestion is coming from the server.
   NTP_SERVER_SIDE_SUGGESTION: 0,
   // The suggestion is coming from the client.
   NTP_CLIENT_SIDE_SUGGESTION: 1,
   // Indicates a tile was rendered, no matter if it's a thumbnail, a gray tile
   // or an external tile.
   NTP_TILE: 2,
-  // The tile uses a local thumbnail image.
-  NTP_THUMBNAIL_TILE: 3,
-  // 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,
   // A NTP Tile has finished loading (successfully or failing).
   NTP_TILE_LOADED: 10,
 };
 
 
 /**
  * The different sources that an NTP tile can have.
  * Note: Keep in sync with common/ntp_logging_events.h
  * @enum {number}
  * @const
@@ skipping 422 matching lines @@
       img.classList.add('large-icon');
       loadedCounter += 1;
       img.addEventListener('load', countLoad);
       img.addEventListener('load', function(ev) {
         thumb.classList.add('large-icon-outer');
       });
       img.addEventListener('error', countLoad);
       img.addEventListener('error', function(ev) {
         thumb.classList.add('failed-img');
         thumb.removeChild(img);
-        logEvent(LOG_TYPE.NTP_THUMBNAIL_ERROR);
       });
       thumb.appendChild(img);
-      logEvent(LOG_TYPE.NTP_THUMBNAIL_TILE);
     } else {
       thumb.classList.add('failed-img');
     }
   } else { // THUMBNAILS
     // We keep track of the outcome of loading possible thumbnails for this
     // tile. Possible values:
     //   - null: waiting for load/error
     //   - false: error
     //   - a string: URL that loaded correctly.
     // This is populated by acceptImage/rejectImage and loadBestImage
@@ skipping 12 matching lines @@
           return;
         }
         if (results[i] != false) {
           img.src = results[i];
           loaded = true;
           return;
         }
       }
       thumb.classList.add('failed-img');
       thumb.removeChild(img);
-      logEvent(LOG_TYPE.NTP_THUMBNAIL_ERROR);
       countLoad();
     };
 
     var acceptImage = function(idx, url) {
       return function(ev) {
         results[idx] = url;
         loadBestImage();
       };
     };
 
     var rejectImage = function(idx) {
       return function(ev) {
         results[idx] = false;
         loadBestImage();
       };
     };
 
     img.title = data.title;
     img.classList.add('thumbnail');
     loadedCounter += 1;
     img.addEventListener('load', countLoad);
     img.addEventListener('error', countLoad);
     img.addEventListener('error', function(ev) {
       thumb.classList.add('failed-img');
       thumb.removeChild(img);
-      logEvent(LOG_TYPE.NTP_THUMBNAIL_ERROR);
     });
     thumb.appendChild(img);
-    logEvent(LOG_TYPE.NTP_THUMBNAIL_TILE);
 
     if (data.thumbnailUrl) {
       img.src = data.thumbnailUrl;
     } else {
       // Get all thumbnailUrls for the tile.
       // They are ordered from best one to be used to worst.
       for (var i = 0; i < data.thumbnailUrls.length; ++i) {
         results.push(null);
       }
       for (var i = 0; i < data.thumbnailUrls.length; ++i) {
@@ skipping 71 matching lines @@
     var html = document.querySelector('html');
     html.dir = 'rtl';
   }
 
   window.addEventListener('message', handlePostMessage);
 };
 
 
 window.addEventListener('DOMContentLoaded', init);
 })();