Oilpan: Move database closing task in ~DatabaseBackendSync to a pre-finalization hook with HeapHash…

Source/modules/webdatabase/DatabaseContext.h

 /*
  * 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 58 matching lines @@
 
     SecurityOrigin* securityOrigin() const;
     bool isContextThread() const;
 
 private:
     explicit DatabaseContext(ExecutionContext*);
 
     void stopSyncDatabases();
 
     RefPtrWillBePersistent<DatabaseThread> m_databaseThread;
+#if ENABLE(OILPAN)
+    class DatabaseCloser {
+    public:
+        explicit DatabaseCloser(DatabaseBackendBase& database) : m_database(database) { }
+        ~DatabaseCloser();
+
+    private:
+        DatabaseBackendBase& m_database;
+    };
+    PersistentHeapHashMap<WeakMember<DatabaseBackendBase>, OwnPtr<DatabaseCloser> > m_openSyncDatabases;
+#else
     // The contents of m_openSyncDatabases are raw pointers. It's safe because
     // DatabaseBackendSync is always closed before destruction.
     HashSet<DatabaseBackendBase*> m_openSyncDatabases;
+#endif
     bool m_hasOpenDatabases; // This never changes back to false, even after the database thread is closed.
     bool m_hasRequestedTermination;
 };
 
 } // namespace WebCore
 
 #endif // DatabaseContext_h