Adds the MostVisitedAction stat. This stat will provide a baseline to compare

chrome/browser/resources/ntp4/most_visited_page.js

 // Copyright (c) 2012 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.
 
 cr.define('ntp', function() {
   'use strict';
 
   var TilePage = ntp.TilePage;
 
   /**
@@ skipping 123 matching lines @@
         // Records an app launch from the most visited page (Chrome will decide
         // whether the url is an app). TODO(estade): this only works for clicks;
         // other actions like "open in new tab" from the context menu won't be
         // recorded. Can this be fixed?
         chrome.send('recordAppLaunchByURL',
                     [encodeURIComponent(this.href),
                      ntp.APP_LAUNCH.NTP_MOST_VISITED]);
         // Records the index of this tile.
         chrome.send('metricsHandler:recordInHistogram',
                     ['NewTabPage.MostVisited', this.index, 8]);
+        chrome.send('mostVisitedAction',
+                    [ntp.NtpFollowAction.CLICKED_TILE]);
       }
     },
 
     /**
      * Allow blacklisting most visited site using the keyboard.
      */
     handleKeyDown_: function(e) {
       if (!cr.isMac && e.keyCode == 46 || // Del
           cr.isMac && e.metaKey && e.keyCode == 8) { // Cmd + Backspace
         this.blacklist_();
@@ skipping 128 matching lines @@
     return el;
   }
 
   MostVisitedPage.prototype = {
     __proto__: TilePage.prototype,
 
     initialize: function() {
       this.classList.add('most-visited-page');
       this.data_ = null;
       this.mostVisitedTiles_ = this.getElementsByClassName('most-visited real');
+
+      this.addEventListener('carddeselected', this.handleCardDeselected_);
+      this.addEventListener('cardselected', this.handleCardSelected_);
     },
 
     /**
      * Create blank (filler) tiles.
      * @private
      */
     createTiles_: function() {
       for (var i = 0; i < THUMBNAIL_COUNT; i++) {
         this.appendTile(new MostVisited());
       }
     },
 
     /**
      * Update the tiles after a change to |data_|.
      */
     updateTiles_: function() {
       for (var i = 0; i < THUMBNAIL_COUNT; i++) {
         var page = this.data_[i];
         var tile = this.mostVisitedTiles_[i];
 
         if (i >= this.data_.length)
           tile.reset();
         else
           tile.updateForData(page);
       }
     },
 
     /**
+     * Handles the 'card deselected' event (i.e. the user clicked to another
+     * pane).
+     * @param {Event} e The CardChanged event.
+     */
+    handleCardDeselected_: function(e) {
+      if (!document.documentElement.classList.contains('starting-up')) {
+        chrome.send('mostVisitedAction',
+                    [ntp.NtpFollowAction.CLICKED_OTHER_NTP_PANE]);
+      }
+    },
+
+    /**
+     * Handles the 'card selected' event (i.e. the user clicked to select the
+     * Most Visited pane).
+     * @param {Event} e The CardChanged event.
+     */
+    handleCardSelected_: function(e) {
+      if (!document.documentElement.classList.contains('starting-up'))
+        chrome.send('mostVisitedSelected');
+    },
+
+    /**
      * Array of most visited data objects.
      * @type {Array}
      */
     get data() {
       return this.data_;
     },
     set data(data) {
       var startTime = Date.now();
 
       // The first time data is set, create the tiles.
@@ skipping 11 matching lines @@
     /** @inheritDoc */
     shouldAcceptDrag: function(e) {
       return false;
     },
 
     /** @inheritDoc */
     heightForWidth: heightForWidth,
   };
 
   /**
+   * Executed once the NTP has loaded. Checks if the Most Visited pane is
+   * shown or not. If it is shown, the 'mostVisitedSelected' message is sent
+   * to the C++ code, to record the fact that the user has seen this pane.
+   */
+  MostVisitedPage.onLoaded = function() {
+    if (ntp.getCardSlider() &&
+        ntp.getCardSlider().currentCardValue &&
+        ntp.getCardSlider().currentCardValue.classList
+        .contains('most-visited-page')) {
+      chrome.send('mostVisitedSelected');
+    }
+  }
+
+  /**
    * We've gotten additional Most Visited data. Update our old data with the
    * new data. The ordering of the new data is not important, except when a
    * page is pinned. Thus we try to minimize re-ordering.
    * @param {Array} oldData The current Most Visited page list.
    * @param {Array} newData The new Most Visited page list.
    * @return {Array} The merged page list that should replace the current page
    *     list.
    */
   function refreshData(oldData, newData) {
     oldData = oldData.slice(0, THUMBNAIL_COUNT);
@@ skipping 56 matching lines @@
     }
 
     return oldData;
   };
 
   return {
     MostVisitedPage: MostVisitedPage,
     refreshData: refreshData,
   };
 });
+
+document.addEventListener('ntpLoaded', ntp.MostVisitedPage.onLoaded);