DevTools: Get rid of Element.prototype.enableStyleClass

Source/devtools/front_end/Layers3DView.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 236 matching lines @@
     /**
      * @param {!Element} element
      */
     _updateLayerElement: function(element)
     {
         var layer = element.__layerDetails.layer;
         var style = element.style;
         var isContentRoot = layer === this._model.contentRoot();
         var parentElement = isContentRoot ? this._rotatingContainerElement : this._elementForLayer(layer.parent());
         element.__layerDetails.depth = parentElement.__layerDetails ? parentElement.__layerDetails.depth + 1 : 0;
-        element.enableStyleClass("invisible", layer.invisible());
+        element.classList.toggle("invisible", layer.invisible());
         this._updateElementColor(element);
         if (parentElement !== element.parentElement)
             parentElement.appendChild(element);
 
         style.width  = layer.width() + "px";
         style.height  = layer.height() + "px";
         this._updatePaintRect(element);
         if (isContentRoot)
             return;
 
@@ skipping 172 matching lines @@
  * @param {!WebInspector.Layer} layer
  * @param {!Element} paintRectElement
  */
 WebInspector.LayerDetails = function(layer, paintRectElement)
 {
     this.layer = layer;
     this.depth = 0;
     this.paintRectElement = paintRectElement;
     this.paintCount = 0;
 }