DevTools: Get rid of Element.prototype.enableStyleClass

Source/devtools/front_end/PlatformFontsSidebarPane.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 73 matching lines @@
      * @param {?Array.<!CSSAgent.PlatformFontUsage>} platformFonts
      */
     _refreshUI: function(node, cssFamilyName, platformFonts)
     {
         if (this._node !== node)
             return;
 
         this._fontStatsSection.removeChildren();
 
         var isEmptySection = !platformFonts || !platformFonts.length;
-        this._sectionTitle.enableStyleClass("hidden", isEmptySection);
+        this._sectionTitle.classList.toggle("hidden", isEmptySection);
         if (isEmptySection)
             return;
         platformFonts.sort(function (a, b) {
             return b.glyphCount - a.glyphCount;
         });
         for (var i = 0; i < platformFonts.length; ++i) {
             var fontStatElement = this._fontStatsSection.createChild("div", "font-stats-item");
 
             var fontNameElement = fontStatElement.createChild("span", "font-name");
             fontNameElement.textContent = platformFonts[i].familyName;
 
             var fontDelimeterElement = fontStatElement.createChild("span", "delimeter");
             fontDelimeterElement.textContent = "\u2014";
 
             var fontUsageElement = fontStatElement.createChild("span", "font-usage");
             var usage = platformFonts[i].glyphCount;
             fontUsageElement.textContent = usage === 1 ? WebInspector.UIString("%d glyph", usage) : WebInspector.UIString("%d glyphs", usage);
         }
     },
 
     __proto__: WebInspector.SidebarPane.prototype
 }