Timeline: fix a bunch of references to out-of-file privates

third_party/WebKit/Source/devtools/front_end/layers/LayerTreeModel.js

 /*
  * 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 176 matching lines @@
       return;
     var root;
     var oldLayersById = this._layersById;
     this._layersById = {};
     for (var i = 0; i < layers.length; ++i) {
       var layerId = layers[i].layerId;
       var layer = oldLayersById[layerId];
       if (layer)
         layer._reset(layers[i]);
       else
-        layer = new Layers.AgentLayer(this._target, layers[i]);
+        layer = new Layers.AgentLayer(this.target(), layers[i]);
       this._layersById[layerId] = layer;
       var backendNodeId = layers[i].backendNodeId;
       if (backendNodeId)
         layer._setNode(this._backendNodeIdToNode.get(backendNodeId));
       if (!this.contentRoot() && layer.drawsContent())
         this.setContentRoot(layer);
       var parentId = layer.parentId();
       if (parentId) {
         var parent = this._layersById[parentId];
         if (!parent)
@@ skipping 352 matching lines @@
 
   /**
    * @override
    * @param {!Protocol.LayerTree.LayerId} layerId
    * @param {!Protocol.DOM.Rect} clipRect
    */
   layerPainted(layerId, clipRect) {
     this._layerTreeModel._layerPainted(layerId, clipRect);
   }
 };