Rollback transactions by observing them weakly from DatabaseSync.

Source/modules/webdatabase/DatabaseSync.h

 /*
  * Copyright (C) 2010 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 58 matching lines @@
     {
         setLastErrorMessage(String::format("%s (%d, %s)", message, sqliteCode, sqliteMessage));
     }
 
 private:
     DatabaseSync(PassRefPtr<DatabaseContext>, const String& name,
         const String& expectedVersion, const String& displayName, unsigned long estimatedSize);
     static PassRefPtrWillBeRawPtr<DatabaseSync> create(ExecutionContext*, PassRefPtrWillBeRawPtr<DatabaseBackendBase>);
 
     void runTransaction(PassOwnPtr<SQLTransactionSyncCallback>, bool readOnly, ExceptionState&);
-    void rollbackTransaction(PassRefPtr<SQLTransactionSync>);
+    void rollbackTransaction(SQLTransactionSync&);
 
     String m_lastErrorMessage;
 
     friend class DatabaseManager;
     friend class DatabaseServer; // FIXME: remove this when the backend has been split out.
+
+#if ENABLE(OILPAN)
+public:
+    void registerTransaction(SQLTransactionSync*);
+
+private:
+    class TransactionObserver {
+    public:
+        TransactionObserver(SQLTransactionSync* sync) : m_sync(sync) { }
+        ~TransactionObserver();

[zerny-chromium, 2014/03/17 09:27:00]

private:

+        SQLTransactionSync* m_sync;
+    };
+
+    typedef PersistentHeapHashMap<WeakMember<SQLTransactionSync>, OwnPtr<TransactionObserver> > ObserverMap;
+    GC_PLUGIN_IGNORE("http://crbug.com/353083")
+    ObserverMap m_observers;
+#endif
+
 };
 
 } // namespace WebCore
 
 #endif