Devtools Animations: Support multiple frames in the animation timeline

Source/devtools/front_end/sdk/AnimationModel.js

 // Copyright (c) 2014 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.
 
 
 /**
  * @constructor
  * @extends {WebInspector.SDKModel}
  * @param {!WebInspector.Target} target
  */
@@ skipping 141 matching lines @@
     playbackRate: function()
     {
         return this._payload.playbackRate;
     },
 
     /**
      * @return {number}
      */
     startTime: function()
     {
-        return this._payload.startTime;
+        return this._startTime === undefined ? this._payload.startTime : this._startTime;
     },
 
     /**
+     * @param {number} startTime
+     */
+    updateStartTime: function(startTime)
+    {
+        this._startTime = startTime;
+    },
+
+    /**
      * @return {number}
      */
     endTime: function()
     {
         if (!this.source().iterations)
             return Infinity;
         return this.startTime() + this.source().delay() + this.source().duration() * this.source().iterations() + this.source().endDelay();
     },
 
     /**
@@ skipping 300 matching lines @@
 
     /**
      * @override
      * @param {string} playerId
      */
     animationPlayerCanceled: function(playerId)
     {
         this._animationModel.animationPlayerCanceled(playerId);
     }
 }