Use a correct scale factor for Gaia avatar images

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">
 
 /**
  * The global object.
  * @type {!Object}
  * @const
@@ skipping 57 matching lines @@
   // WebKit has a bug when it comes to URLs that end with \
   // https://bugs.webkit.org/show_bug.cgi?id=28885
   if (/\\\\$/.test(s2)) {
     // Add a space to work around the WebKit bug.
     s2 += ' ';
   }
   return 'url("' + s2 + '")';
 }
 
 /**
+ * Returns the URL of the image, or an image set of URLs for the profile avatar.
+ * Default avatars have resources available for multiple scalefactors, whereas
+ * the GAIA profile image only comes in one size.
+
+ * @param {string} url The path of the image.
+ * @return {string} The url, or an image set of URLs of the avatar image.
+ */
+function getProfileAvatarIcon(path) {
+  var chromeThemePath = 'chrome://theme';
+  var isDefaultAvatar =
+      (path.slice(0, chromeThemePath.length) == chromeThemePath);
+  return isDefaultAvatar ? imageset(path + '@scalefactorx'): url(path);
+}
+
+/**
  * Generates a CSS -webkit-image-set for a chrome:// url.
  * An entry in the image set is added for each of getSupportedScaleFactors().
  * The scale-factor-specific url is generated by replacing the first instance of
  * 'scalefactor' in |path| with the numeric scale factor.
  * @param {string} path The URL to generate an image set for.
  *     'scalefactor' should be a substring of |path|.
  * @return {string} The CSS -webkit-image-set.
  */
 function imageset(path) {
   var supportedScaleFactors = getSupportedScaleFactors();
@@ skipping 314 matching lines @@
  * @param {number} maxLength The maximum length allowed for the string.
  * @return {string} The original string if its length does not exceed
  *     |maxLength|. Otherwise the first |maxLength| - 1 characters with '...'
  *     appended.
  */
 function elide(original, maxLength) {
   if (original.length <= maxLength)
     return original;
   return original.substring(0, maxLength - 1) + '\u2026';
 }