Add a static Google Doodle to the experimental app list start page.

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 30 matching lines @@
   /**
    * Invoked when the app-list bubble is shown.
    *
    * @param {boolean} hotwordEnabled Whether the hotword is enabled or not.
    */
   function onAppListShown(hotwordEnabled) {
     speechManager.onShown(hotwordEnabled);
   }
 
   /**
+   * Invoked when the app-list doodle is updated.
+   *
+   * @param {Object} data The data object representing the current doodle.

[Matt Giuca, 2015/01/29 08:00:53]

Any reason you pass the whole JSON in? Why not grab transparent_large_image in
the C++ code and pass it in as a string.

Then also you won't need to do base_url + transparent_large_image (you can do
that in the C++ as well).

[calamity, 2015/01/30 05:09:14]

There are other fields we're interested in such as alt text and target url. I'll
add them in a follow up.

[Matt Giuca, 2015/02/02 06:23:14]

Acknowledged.

+   */
+  function onAppListDoodleUpdated(data, base_url) {
+    var defaultLogo = $('logo');
+    var doodle = $('doodle');
+    if (!data.ddljson || !data.ddljson.transparent_large_image) {
+      defaultLogo.style.display = 'block';
+      doodle.style.display = 'none';
+      return;
+    }
+
+    doodle.onload = function() {
+      defaultLogo.style.display = 'none';
+      doodle.style.display = 'block';
+    };
+    doodle.src = base_url + data.ddljson.transparent_large_image.url;
+  }
+
+  /**
    * Invoked when the app-list bubble is hidden.
    */
   function onAppListHidden() {
     speechManager.onHidden();
   }
 
   /**
    * Invoked when the user explicitly wants to toggle the speech recognition
    * state.
    */
   function toggleSpeechRecognition() {
     speechManager.toggleSpeechRecognition();
   }
 
   return {
     initialize: initialize,
     setHotwordEnabled: setHotwordEnabled,
     setNaclArch: setNaclArch,
+    onAppListDoodleUpdated: onAppListDoodleUpdated,
     onAppListShown: onAppListShown,
     onAppListHidden: onAppListHidden,
     toggleSpeechRecognition: toggleSpeechRecognition
   };
 });
 
 document.addEventListener('DOMContentLoaded', appList.startPage.initialize);