DevTools: Get rid of Element.prototype.enableStyleClass

Source/devtools/front_end/UISourceCodeFrame.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 139 matching lines @@
         if (!this._muteSourceCodeEvents) {
             this._innerSetContent(this._uiSourceCode.workingCopy());
             this.onUISourceCodeContentChanged();
         }
         this._textEditor.markClean();
         this._updateStyle();
     },
 
     _updateStyle: function()
     {
-        this.element.enableStyleClass("source-frame-unsaved-committed-changes", this._uiSourceCode.hasUnsavedCommittedChanges());
+        this.element.classList.toggle("source-frame-unsaved-committed-changes", this._uiSourceCode.hasUnsavedCommittedChanges());
     },
 
     onUISourceCodeContentChanged: function()
     {
     },
 
     /**
      * @param {string} content
      */
     _innerSetContent: function(content)
@@ skipping 10 matching lines @@
         contextMenu.appendSeparator();
     },
 
     dispose: function()
     {
         this.detach();
     },
 
     __proto__: WebInspector.SourceFrame.prototype
 }