Oilpan: Remove support for tracing off-heap HashSets.

Source/modules/webdatabase/SQLTransactionCoordinator.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 43 matching lines @@
     void shutdown();
 private:
     typedef Deque<RefPtrWillBeMember<SQLTransactionBackend> > TransactionsQueue;
     struct CoordinationInfo {
         TransactionsQueue pendingTransactions;
         WillBeHeapHashSet<RefPtrWillBeMember<SQLTransactionBackend> > activeReadTransactions;
         RefPtrWillBeMember<SQLTransactionBackend> activeWriteTransaction;
 
         void trace(Visitor* visitor)
         {
+#if ENABLE(OILPAN)
             visitor->trace(pendingTransactions);
             visitor->trace(activeReadTransactions);
             visitor->trace(activeWriteTransaction);
+#endif
         }
         ALLOW_ONLY_INLINE_ALLOCATION();
     };
     // Maps database names to information about pending transactions
     typedef WillBeHeapHashMap<String, CoordinationInfo> CoordinationInfoHeapMap;
     CoordinationInfoHeapMap m_coordinationInfoMap;
     bool m_isShuttingDown;
 
     void processPendingTransactions(CoordinationInfo&);
 };
 
 } // namespace WebCore
 
 #endif // SQLTransactionCoordinator_h