Add support for favicon scale factor in WebUI

chrome/browser/resources/shared/js/util.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.
 
 /**
  * The global object.
  * @type {!Object}
  * @const
  */
 var global = this;
@@ skipping 208 matching lines @@
  * @param {string} value The value of the param.
  * @return {string} The new URL.
  */
 function appendParam(url, key, value) {
   var param = encodeURIComponent(key) + '=' + encodeURIComponent(value);
 
   if (url.indexOf('?') == -1)
     return url + '?' + param;
   return url + '&' + param;
 }
+
+/**
+ * Creates a new URL for a favicon request.
+ * @param {string} url The url for the favicon.
+ * @param {number=} opt_size Optional preferred size of the favicon.
+ * @return {string} Updated URL for the favicon.
+ */
+function getFaviconURL(url, opt_size) {
+  var size = opt_size || 16;
+  return 'chrome://favicon/size/' + size + '@' +
+      window.devicePixelRatio + 'x/' + url;
+}