Simplify Supplementables post Oilpan.

third_party/WebKit/Source/core/frame/Screen.cpp

 /*
  * Copyright (C) 2007 Apple 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.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 126 matching lines @@
         return 0;
     if (host->settings().reportScreenSizeInPhysicalPixelsQuirk()) {
         WebScreenInfo screenInfo = host->chromeClient().screenInfo();
         return lroundf(screenInfo.availableRect.width * screenInfo.deviceScaleFactor);
     }
     return host->chromeClient().screenInfo().availableRect.width;
 }
 
 DEFINE_TRACE(Screen)
 {
-    HeapSupplementable<Screen>::trace(visitor);
     DOMWindowProperty::trace(visitor);
+    Supplementable<Screen>::trace(visitor);
 }
 
 } // namespace blink