[DevTools] Remove remaining usages of global properties.

Source/devtools/front_end/ui/PieChart.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 96 matching lines @@
         var largeArc = sliceAngle > Math.PI ? 1 : 0;
         path.setAttribute("d", "M0,0 L" + x1 + "," + y1 + " A1,1,0," + largeArc + ",1," + x2 + "," + y2 + " Z");
         path.setAttribute("fill", color);
         this._slices.push(path);
     },
 
     /**
      * @param {!Element} parent
      * @param {string} childType
      * @return {!Element}
+     * @suppressGlobalPropertiesCheck
      */
     _createSVGChild: function(parent, childType)
     {
         var child = document.createElementNS("http://www.w3.org/2000/svg", childType);
         parent.appendChild(child);
         return child;
     }
 }