Add UMA stats for which icon types are shown and clicked on the NTP.

chrome/android/javatests/src/org/chromium/chrome/browser/ntp/FakeMostVisitedSites.java

 // 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.
 
 package org.chromium.chrome.browser.ntp;
 
 import org.chromium.base.ThreadUtils;
 import org.chromium.chrome.browser.profiles.MostVisitedSites;
 import org.chromium.chrome.browser.profiles.Profile;
 
@@ skipping 31 matching lines @@
                         mMostVisitedUrls.clone());
             }
         });
     }
 
     @Override
     public void getURLThumbnail(String url, final ThumbnailCallback callback) {
         ThreadUtils.postOnUiThread(new Runnable() {
             @Override
             public void run() {
-                callback.onMostVisitedURLsThumbnailAvailable(null);
+                callback.onMostVisitedURLsThumbnailAvailable(null, true);
             }
         });
     }
 
     @Override
     public void blacklistUrl(String url) {
         mBlacklistedUrls.add(url);
     }
 
     /**
      * @return Whether blacklistUrl() has been called on the given url.
      */
     public boolean isUrlBlacklisted(String url) {
         return mBlacklistedUrls.contains(url);
     }
 
     @Override
-    public void recordOpenedMostVisitedItem(int index) {
+    public void recordTileTypeMetrics(int[] tileTypes) {
+        // Metrics are stubbed out.
+    }
+
+    @Override
+    public void recordOpenedMostVisitedItem(int index, int tileType) {
         //  Metrics are stubbed out.
     }
 }