/**
 * @license
 * Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */

(function(scope) {

  'use strict';

  // polyfill performance.now

  if (!window.performance) {
    var start = Date.now();
    // only at millisecond precision
    window.performance = {now: function(){ return Date.now() - start }};
  }

  // polyfill for requestAnimationFrame

  if (!window.requestAnimationFrame) {
    window.requestAnimationFrame = (function() {
      var nativeRaf = window.webkitRequestAnimationFrame ||
        window.mozRequestAnimationFrame;

      return nativeRaf ?
        function(callback) {
          return nativeRaf(function() {
            callback(performance.now());
          });
        } :
        function( callback ){
          return window.setTimeout(callback, 1000 / 60);
        };
    })();
  }

  if (!window.cancelAnimationFrame) {
    window.cancelAnimationFrame = (function() {
      return  window.webkitCancelAnimationFrame ||
        window.mozCancelAnimationFrame ||
        function(id) {
          clearTimeout(id);
        };
    })();
  }

})(window.WebComponents);
