Make the DatabaseTracker thread-safe.

WebCore/storage/Database.h

 /*
  * Copyright (C) 2007, 2008 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 87 matching lines @@
     String fileName() const;
 
     bool getVersionFromDatabase(String&);
     bool setVersionInDatabase(const String&);
     void setExpectedVersion(const String&);
     bool versionMatchesExpected() const;
 
     void markAsDeletedAndClose();
     bool deleted() const { return m_deleted; }
 
-    void close();
+    void close(bool removeDatabaseFromContext);
     bool opened() const { return m_opened; }
 
     void stop();
     bool stopped() const { return m_stopped; }
 
     unsigned long long databaseSize() const;
     unsigned long long maximumSize() const;
 
 // Called from DatabaseThread, must be prepared to work on the background thread
     void resetAuthorizer();
@@ skipping 55 matching lines @@
 namespace WebCore {
 class Database : public ThreadSafeShared<Database> {
 public:
     static const String& databaseInfoTableName();
 };
 } // namespace WebCore
 
 #endif // ENABLE(DATABASE)
 
 #endif // Database_h