DevTools: add 3D layer view to Layer panel

Source/devtools/front_end/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 91 matching lines @@
             delete this._pendingRequestLayersCallbacks;
         }
         function onDocumentAvailable()
         {
             LayerTreeAgent.getLayers(undefined, onGetLayers.bind(this))
         }
         WebInspector.domAgent.requestDocument(onDocumentAvailable.bind(this));
     },
 
     /**
+     * @param {string} id
+     * @return {WebInspector.Layer?}
+     */
+    layerById: function(id)
+    {
+        return this._layersById[id];
+    },
+
+    /**
      * @param{Array.<LayerTreeAgent.Layer>} payload
      */
     _repopulate: function(payload)
     {
         var oldLayersById = this._layersById;
         this._layersById = {};
         for (var i = 0; i < payload.length; ++i) {
             var layer = oldLayersById[payload[i].layerId];
             if (layer)
                 layer._reset(payload[i]);
@@ skipping 138 matching lines @@
 {
     this._layerTreeModel = layerTreeModel;
 }
 
 WebInspector.LayerTreeDispatcher.prototype = {
     layerTreeDidChange: function()
     {
         this._layerTreeModel._layerTreeChanged();
     }
 }