[Offline pages on the NTP] Add UMA for offline-available NTP tiles

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.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 android.annotation.TargetApi;
 import android.app.Activity;
 import android.app.ActivityManager;
 import android.app.Dialog;
@@ skipping 513 matching lines @@
             if (mIsDestroyed) return;
 
             recordNTPShown();
 
             int tileTypes[] = new int[items.length];
             for (int i = 0; i < items.length; i++) {
                 tileTypes[i] = items[i].getTileType();
             }
             mMostVisitedSites.recordTileTypeMetrics(tileTypes);
 
+            if (isNtpOfflinePagesEnabled()) {
+                final int maxNumTiles = 12;
+                for (int i = 0; i < items.length; i++) {
+                    if (items[i].isOfflineAvailable()) {
+                        RecordHistogram.recordEnumeratedHistogram(
+                                "NewTabPage.TileOfflineAvailable", i, maxNumTiles);
+                    }
+                }
+            }
+
             SyncSessionsMetrics.recordYoungestForeignTabAgeOnNTP();
         }
     };
 
     /**
      * Constructs a NewTabPage.
      * @param activity The activity used for context to create the new tab page's View.
      * @param tab The Tab that is showing this new tab page.
      * @param tabModelSelector The TabModelSelector used to open tabs.
      */
@@ skipping 268 matching lines @@
     @Override
     public boolean shouldCaptureThumbnail() {
         return mNewTabPageView.shouldCaptureThumbnail();
     }
 
     @Override
     public void captureThumbnail(Canvas canvas) {
         mNewTabPageView.captureThumbnail(canvas);
     }
 }