Add UMA for the app list doodle being clicked.

chrome/browser/resources/app_list/start_page.js

 // Copyright 2013 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 App launcher start page implementation.
  */
 
 <include src="speech_manager.js">
 
@@ skipping 94 matching lines @@
       setDoodleVisible(true);
     };
     doodleImage.src = doodleData.transparent_large_image.url;
 
     if (doodleData.target_url) {
       var doodleLink = document.createElement('a');
       doodleLink.id = 'doodle_link';
       doodleLink.href = doodleData.target_url;
       doodleLink.target = '_blank';
       doodleLink.appendChild(doodleImage);
+      doodleLink.onclick = function() {
+        chrome.send('doodleClicked');
+        return true;
+      };
       this.doodle.appendChild(doodleLink);
     } else {
       this.doodle.appendChild(doodleImage);
     }
     $('logo_container').appendChild(this.doodle);
   }
 
   /**
    * Invoked when the app-list bubble is hidden.
    */
@@ skipping 15 matching lines @@
     setNaclArch: setNaclArch,
     onAppListDoodleUpdated: onAppListDoodleUpdated,
     onAppListShown: onAppListShown,
     onAppListHidden: onAppListHidden,
     toggleSpeechRecognition: toggleSpeechRecognition
   };
 });
 
 document.addEventListener('contextmenu', function(e) { e.preventDefault(); });
 document.addEventListener('DOMContentLoaded', appList.startPage.initialize);