DevTools: Avoid private member access in non-profiler code

Source/devtools/front_end/sdk/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 64 matching lines @@
         this._enabled = false;
         this._layerTree = null;
         LayerTreeAgent.disable();
     },
 
     enable: function()
     {
         if (this._enabled)
             return;
         this._enabled = true;
-        this._layerTree = new WebInspector.AgentLayerTree(this._target);
+        this._layerTree = new WebInspector.AgentLayerTree(this.target());
         this._lastPaintRectByLayerId = {};
         LayerTreeAgent.enable();
     },
 
     /**
      * @param {!WebInspector.LayerTreeBase} layerTree
      */
     setLayerTree: function(layerTree)
     {
         this.disable();
@@ skipping 218 matching lines @@
         var layer = /** @type {?WebInspector.TracingLayer} */ (oldLayersById[payload.layer_id]);
         if (layer)
             layer._reset(payload);
         else
             layer = new WebInspector.TracingLayer(payload);
         this._layersById[payload.layer_id] = layer;
         if (!this._contentRoot && payload.draws_content)
             this._contentRoot = layer;
 
         if (payload.owner_node && this._backendNodeIdToNodeId[payload.owner_node])
-            layer._setNode(this._target.domModel.nodeForId(this._backendNodeIdToNodeId[payload.owner_node]));
+            layer._setNode(this.target().domModel.nodeForId(this._backendNodeIdToNodeId[payload.owner_node]));
 
         for (var i = 0; payload.children && i < payload.children.length; ++i)
             layer.addChild(this._innerSetLayers(oldLayersById, payload.children[i]));
         return layer;
     },
 
     /**
      * @param {!Array.<number>} nodeIdsToResolve
      * @param {!Object} seenNodeIds
      * @param {!WebInspector.TracingLayerPayload} payload
@@ skipping 69 matching lines @@
         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 WebInspector.AgentLayer(layers[i]);
             this._layersById[layerId] = layer;
             if (layers[i].backendNodeId) {
-                layer._setNode(this._target.domModel.nodeForId(this._backendNodeIdToNodeId[layers[i].backendNodeId]));
+                layer._setNode(this.target().domModel.nodeForId(this._backendNodeIdToNodeId[layers[i].backendNodeId]));
                 if (!this._contentRoot)
                     this._contentRoot = layer;
             }
             var parentId = layer.parentId();
             if (parentId) {
                 var parent = this._layersById[parentId];
                 if (!parent)
                     console.assert(parent, "missing parent " + parentId + " for layer " + layerId);
                 parent.addChild(layer);
             } else {
@@ skipping 753 matching lines @@
 
     /**
      * @param {!LayerTreeAgent.LayerId} layerId
      * @param {!DOMAgent.Rect} clipRect
      */
     layerPainted: function(layerId, clipRect)
     {
         this._layerTreeModel._layerPainted(layerId, clipRect);
     }
 }