Web Animations: Remove timeLag from Player API and model

Source/core/animation/AnimationPlayer.idl

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 19 matching lines @@
 
 [
     RuntimeEnabled=WebAnimationsElementAnimate,
     NoInterfaceObject,
     WillBeGarbageCollected,
     ActiveDOMObject,
 ] interface AnimationPlayer : EventTarget {
     [RuntimeEnabled=WebAnimationsAPI]          attribute AnimationNode? source;
     [RuntimeEnabled=WebAnimationsAPI]          attribute double     startTime;
     [RuntimeEnabled=WebAnimationsAPI]          attribute double     currentTime;
-    [RuntimeEnabled=WebAnimationsAPI] readonly attribute double     timeLag;
     [RuntimeEnabled=WebAnimationsAPI]          attribute double     playbackRate;
     [RuntimeEnabled=WebAnimationsAPI] readonly attribute boolean    paused;
     [RuntimeEnabled=WebAnimationsAPI] readonly attribute boolean    finished;
     [RuntimeEnabled=WebAnimationsAPI, RaisesException] void finish();
     [RuntimeEnabled=WebAnimationsAPI] void play();
     [RuntimeEnabled=WebAnimationsAPI] void pause();
     [RuntimeEnabled=WebAnimationsAPI] void reverse();
 
     void cancel();
     [MeasureAs=AnimationPlayerFinishEvent] attribute EventHandler onfinish;
 };