DevTools: Get rid of Element.prototype.enableStyleClass

Source/devtools/front_end/SplitView.js

 /*
  * Copyright (C) 2012 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:
  *
  * 1. Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *
@@ skipping 324 matching lines @@
         this._updateLayout(animate);
         this._updateShowMode(WebInspector.SplitView.ShowMode.Both);
     },
 
     /**
      * @param {boolean} resizable
      */
     setResizable: function(resizable)
     {
         this._resizable = resizable;
-        this._resizerElement.enableStyleClass("hidden", !resizable);
+        this._resizerElement.classList.toggle("hidden", !resizable);
     },
 
     /**
      * @param {number} size
      */
     setSidebarSize: function(size)
     {
         this._innerSetSidebarSize(size);
         this._saveSetting();
     },
@@ skipping 473 matching lines @@
     _updateShowHideSidebarButton: function()
     {
         if (!this._showHideSidebarButton)
             return;
         this._showHideSidebarButton.state = this._isShowingOne === this.isSidebarSecond() ? "left" : "right";
         this._showHideSidebarButton.title = this._isShowingOne ? WebInspector.UIString("Show %s", this._showHideSidebarButtonTitle) : WebInspector.UIString("Hide %s", this._showHideSidebarButtonTitle);
     },
 
     __proto__: WebInspector.View.prototype
 }