[Search] Add a header image to the promo flow.

chrome/browser/resources/contextual_search/promo.js

 /* Copyright 2014 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.
 */
 
+<include src="../../../../ui/webui/resources/js/util.js">
+<include src="../../../../ui/webui/resources/js/load_time_data.js">
+
 /**
- * On load, registers the handler to add the 'hide' class to the container
- * element in order to hide it.
+ * Once the DOM is loaded, determine if the header image is to be kept and
+ * register a handler to add the 'hide' class to the container element in order
+ * to hide it.
  */
-window.onload = function() {
+document.addEventListener('DOMContentLoaded', function(event) {
+  if (config['hideHeader']) {

[huangs, 2014/09/23 13:44:38]

NIT: I'm a bit worried about flicker on slow machines: would the header image
appear momentarily before disappearing?  Please check, but don't have to change
in this CL.

[Mathieu, 2014/09/23 13:50:08]

In this context it's really the best I can think of. The page is rendered
offscreen, so I'm not too worried about flicker.

+    $('container').removeChild($('header-image'));
+  }
   $('optin-label').addEventListener('click', function() {
     $('container').classList.add('hide');
   });
-};
+});
 
 /**
  * Returns the height of the content. Method called from Chrome to properly size
  * the view embedding it.
  * @return {number} The height of the content, in pixels.
  */
 function getContentHeight() {
   return $('container').clientHeight;
 }