DevTools: Move DOMNode.appropriateSelectorFor() into DOMPresentationUtil.

Source/devtools/front_end/LayerTree.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 180 matching lines @@
     {
         var selection = document.createElement("div");
         selection.className = "selection";
         this.listItemElement.insertBefore(selection, this.listItemElement.firstChild);
     },
 
     _update: function()
     {
         var layer = /** @type {WebInspector.Layer} */ (this.representedObject);
         var nodeId = layer.nodeIdForSelfOrAncestor();
-        var node = nodeId && WebInspector.domAgent.nodeForId(nodeId);
+        var node = nodeId ? WebInspector.domAgent.nodeForId(nodeId) : null;
         var title = document.createDocumentFragment();
         title.createChild("div", "selection");
-        title.appendChild(document.createTextNode(node ? node.appropriateSelectorFor(false) :  "#" + layer.id()));
+        title.appendChild(document.createTextNode(node ? WebInspector.DOMPresentationUtils.appropriateSelectorFor(node, false) :  "#" + layer.id()));
         var details = title.createChild("span", "dimmed");
         details.textContent = WebInspector.UIString(" (%d × %d)", layer.width(), layer.height());
         this.title = title;
     },
 
     onselect: function()
     {
         this._layerTree._selectedNodeChanged(this);
     },
 
     /**
      * @param {boolean} hovered
      */
     setHovered: function(hovered)
     {
         this.listItemElement.enableStyleClass("hovered", hovered);
     },
 
     __proto__: TreeElement.prototype
 }