Add metrics for interactions with the Apps Launcher promo dialog.

chrome/browser/resources/ntp4/new_tab.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.
 
 /**
  * @fileoverview New tab page
  * This is the main code for the new tab page used by touch-enabled Chrome
  * browsers.  For now this is still a prototype.
  */
 
@@ skipping 104 matching lines @@
    */
   function onLoad() {
     sectionsToWaitFor = 0;
     if (loadTimeData.getBoolean('showMostvisited'))
       sectionsToWaitFor++;
     if (loadTimeData.getBoolean('showApps')) {
       sectionsToWaitFor++;
       if (loadTimeData.getBoolean('showAppLauncherPromo')) {
         $('app-launcher-promo-close-button').addEventListener('click',
             function() { chrome.send('stopShowingAppLauncherPromo'); });
+        $('apps-promo-learn-more').addEventListener('click',
+            function() { chrome.send('onLearnMore'); });
       }
     }
     if (loadTimeData.getBoolean('isDiscoveryInNTPEnabled'))
       sectionsToWaitFor++;
     measureNavDots();
 
     // Load the current theme colors.
     themeChanged();
 
     newTabView = new NewTabView();
@@ skipping 558 matching lines @@
     setFaviconDominantColor: setFaviconDominantColor,
     showNotification: showNotification,
     themeChanged: themeChanged,
     updateLogin: updateLogin
   };
 });
 
 document.addEventListener('DOMContentLoaded', ntp.onLoad);
 
 var toCssPx = cr.ui.toCssPx;