Make getFaviconImageSet work with all expected URL types.

ui/webui/resources/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.
 
 // <include src="assert.js">
 
 /**
  * Alias for document.getElementById. Found elements must be HTMLElements.
  * @param {string} id The ID of the element to find.
  * @return {HTMLElement} The found element or null if not found.
@@ skipping 307 matching lines @@
  */
 function appendParam(url, key, value) {
   var param = encodeURIComponent(key) + '=' + encodeURIComponent(value);
 
   if (url.indexOf('?') == -1)
     return url + '?' + param;
   return url + '&' + param;
 }
 
 /**
+ * A regular expression for identifying favicon URLs.
+ * @const {!RegExp}
+ * TODO(dpapad): Move all favicon related methods to a new favicon_util.js file
+ * and make this RegExp private.
+ */
+var FAVICON_URL_REGEX = /\.ico$/;

[Dan Beam, 2016/04/27 02:18:31]

nit: /i

[dpapad, 2016/04/27 17:21:47]

Are you suggesting  modifying the regex to /ico$/? This would make it more
likely that it will result in a false positive, imagine a URL like
www.something.com/fantastico which is not a favicon URL. I prefer to keep the
dot matching for this reason.

[dpapad, 2016/04/27 17:24:25]

On second thought, you probably meant adding /i at the end for case
insensitivity. Done.

[Dan Beam, 2016/04/27 18:46:56]

yes, that ^

+
+/**
  * Creates a CSS -webkit-image-set for a favicon request.
- * @param {string} url The url for the favicon.
+ * @param {string} url Either the URL of the original page or of the favicon
+ *     itself.
  * @param {number=} opt_size Optional preferred size of the favicon.
  * @param {string=} opt_type Optional type of favicon to request. Valid values
  *     are 'favicon' and 'touch-icon'. Default is 'favicon'.
  * @return {string} -webkit-image-set for the favicon.
  */
 function getFaviconImageSet(url, opt_size, opt_type) {
   var size = opt_size || 16;
   var type = opt_type || 'favicon';
+
+  // Note: Literals 'iconurl' and 'origin' must match |kIconURLParameter| and
+  // |kOriginParameter| in components/favicon_base/favicon_url_parser.cc.
+  var urlType = FAVICON_URL_REGEX.test(url) ? 'iconurl' : 'origin';
+
   return imageset(
-      'chrome://' + type + '/size/' + size + '@scalefactorx/' + url);
+      'chrome://' + type + '/size/' + size + '@scalefactorx/' +
+      urlType + '/' + url);
 }
 
 /**
  * Creates a new URL for a favicon request for the current device pixel ratio.
  * The URL must be updated when the user moves the browser to a screen with a
  * different device pixel ratio. Use getFaviconImageSet() for the updating to
  * occur automatically.
  * @param {string} url The url for the favicon.
  * @param {number=} opt_size Optional preferred size of the favicon.
  * @param {string=} opt_type Optional type of favicon to request. Valid values
@@ skipping 117 matching lines @@
 }
 
 /**
  * Quote a string so it can be used in a regular expression.
  * @param {string} str The source string.
  * @return {string} The escaped string.
  */
 function quoteString(str) {
   return str.replace(/([\\\.\+\*\?\[\^\]\$\(\)\{\}\=\!\<\>\|\:])/g, '\\$1');
 }