Oilpan: Remove support for tracing off-heap HashSets.

Source/modules/webdatabase/DatabaseContext.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * 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:
  * 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 100 matching lines @@
 
 DatabaseContext::~DatabaseContext()
 {
     // For debug accounting only. We must call this last. The assertions assume
     // this.
     DatabaseManager::manager().didDestructDatabaseContext();
 }
 
 void DatabaseContext::trace(Visitor* visitor)
 {
+#if ENABLE(OILPAN)
     visitor->trace(m_databaseThread);
     visitor->trace(m_openSyncDatabases);
+#endif
 }
 
 // This is called if the associated ExecutionContext is destructing while
 // we're still associated with it. That's our cue to disassociate and shutdown.
 // To do this, we stop the database and let everything shutdown naturally
 // because the database closing process may still make use of this context.
 // It is not safe to just delete the context here.
 void DatabaseContext::contextDestroyed()
 {
     RefPtrWillBeRawPtr<DatabaseContext> protector(this);
@@ skipping 125 matching lines @@
 {
     return executionContext()->securityOrigin();
 }
 
 bool DatabaseContext::isContextThread() const
 {
     return executionContext()->isContextThread();
 }
 
 } // namespace WebCore