DevTools: Get rid of Element.prototype.enableStyleClass

Source/devtools/front_end/CodeMirrorTextEditor.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:
  *
  *     * 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 571 matching lines @@
 
     _disableLongLinesMode: function()
     {
         this._codeMirror.setOption("styleSelectedText", true);
         this._longLinesMode = false;
     },
 
     _updateCodeMirrorMode: function()
     {
         var showWhitespaces = WebInspector.settings.showWhitespacesInEditor.get();
-        this.element.enableStyleClass("show-whitespaces", showWhitespaces);
+        this.element.classList.toggle("show-whitespaces", showWhitespaces);
         this._codeMirror.setOption("mode", showWhitespaces ? this._whitespaceOverlayMode(this._mimeType) : this._mimeType);
     },
 
     /**
      * @param {string} mimeType
      */
     setMimeType: function(mimeType)
     {
         this._mimeType = mimeType;
         if (this._hasLongLines())
             this._enableLongLinesMode();
         else
             this._disableLongLinesMode();
         this._updateCodeMirrorMode();
     },
 
     /**
      * @param {boolean} readOnly
      */
     setReadOnly: function(readOnly)
     {
-        this.element.enableStyleClass("CodeMirror-readonly", readOnly)
+        this.element.classList.toggle("CodeMirror-readonly", readOnly)
         this._codeMirror.setOption("readOnly", readOnly);
     },
 
     /**
      * @return {boolean}
      */
     readOnly: function()
     {
         return !!this._codeMirror.getOption("readOnly");
     },
@@ skipping 1084 matching lines @@
     var backgroundColorRule = backgroundColor ? ".CodeMirror .CodeMirror-selected { background-color: " + backgroundColor + ";}" : "";
     var foregroundColor = InspectorFrontendHost.getSelectionForegroundColor();
     var foregroundColorRule = foregroundColor ? ".CodeMirror .CodeMirror-selectedtext:not(.CodeMirror-persist-highlight) { color: " + foregroundColor + "!important;}" : "";
     if (!foregroundColorRule && !backgroundColorRule)
         return;
 
     var style = document.createElement("style");
     style.textContent = backgroundColorRule + foregroundColorRule;
     document.head.appendChild(style);
 })();