title: requestAnimationFrame is passing unexpected parameters in IE10
body: <p>So I've been a good net citizen, using feature detection to see whether the browser supports <code>requestAnimationFrame</code> and only fall back to a <code>setTimeout</code>-based solution otherwise (something around the lines of <a href="http://paulirish.com/2011/requestanimationframe-for-smart-animating/">Paul Irish's famous post</a>).</p>
  
  <pre class="lang-js prettyprint-override"><code>var NOW = Date.now || function () { return new Date.getTime(); };
  var reqAnimFrame =
          window.requestAnimationFrame ||
          window.webkitRequestAnimationFrame ||
          /*                        ... ||                     */
          function (callback) {
              setTimeout(function () { callback(NOW()); }, 1000 / 60);
          };
  
  var previousTime = NOW();
  function animStep(time) {
      var timePassed = time - previousTime;
      myCharacter.move(myCharacter.speed * timePassed);
      previousTime = time;
      reqAnimationFrame(animStep);
  } 
  
  // start the animation
  reqAnimationFrame(animStep); 
  </code></pre>
  
  <p>This worked great everywhere until Internet Explorer 10 came along. In IE10, the <code>time</code> parameter passed doesn't seem to have anything to do with the current time, screwing up the calculation of <code>timePassed</code>.</p>
  
  <p>What's going on?</p>