Oilpan: cleanup based on review comments after removal of TreeShared.

Source/core/dom/shadow/ShadowRoot.h

 /*
  * Copyright (C) 2011 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.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 110 matching lines @@
     PassRefPtr<Node> cloneNode(ExceptionState& exceptionState) { return cloneNode(true, exceptionState); }
 
     StyleSheetList* styleSheets();
 
     virtual void trace(Visitor*) OVERRIDE;
 
 private:
     ShadowRoot(Document&, ShadowRootType);
     virtual ~ShadowRoot();
 
+#if !ENABLE(OILPAN)
     virtual void dispose() OVERRIDE;
+#endif
+
     virtual void childrenChanged(bool changedByParser, Node* beforeChange, Node* afterChange, int childCountDelta) OVERRIDE;
 
     ShadowRootRareData* ensureShadowRootRareData();
 
     void addChildShadowRoot();
     void removeChildShadowRoot();
     void invalidateDescendantInsertionPoints();
 
     // ShadowRoots should never be cloned.
     virtual PassRefPtr<Node> cloneNode(bool) OVERRIDE { return nullptr; }
@@ skipping 14 matching lines @@
 {
     return adjustedFocusedElement();
 }
 
 DEFINE_NODE_TYPE_CASTS(ShadowRoot, isShadowRoot());
 DEFINE_TYPE_CASTS(ShadowRoot, TreeScope, treeScope, treeScope->rootNode().isShadowRoot(), treeScope.rootNode().isShadowRoot());
 
 } // namespace
 
 #endif