Fixes the regex used to test for the Mac platform.

chrome/browser/resources/ntp/util.js

 // Copyright (c) 2010 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.
 
 // TODO(arv): Move to shared/js once namespaced and tested.
 
 var global = this;
-const IS_MAC = /$Mac/.test(navigator.platform);
+const IS_MAC = /^Mac/.test(navigator.platform);
 
 function $(id) {
   return document.getElementById(id);
 }
 
 function bind(fn, selfObj, var_args) {
   var boundArgs = Array.prototype.slice.call(arguments, 2);
   return function() {
     var args = Array.prototype.slice.call(arguments);
     args.unshift.apply(args, boundArgs);
@@ skipping 58 matching lines @@
     // restore
     global[callbackName] = old;
 
     var args = Array.prototype.slice.call(arguments);
     return callback.apply(global, args);
   };
   chrome.send(name, params);
 }