Manage WebSQL callbacks with OwnPtr instead of refcounting

Source/modules/webdatabase/SQLTransaction.h

Index: Source/modules/webdatabase/SQLTransaction.h
diff --git a/Source/modules/webdatabase/SQLTransaction.h b/Source/modules/webdatabase/SQLTransaction.h
index 29e2a175929203b7cad8f5f9ab2e2fa5921b9c12..2e6058a12a5d4c88593f3fd2f93dbdcc88fe2481 100644
--- a/Source/modules/webdatabase/SQLTransaction.h
+++ b/Source/modules/webdatabase/SQLTransaction.h
@@ -52,20 +52,22 @@ class SQLVoidCallback;
 
 class SQLTransaction : public SQLTransactionStateMachine<SQLTransaction>, public AbstractSQLTransaction, public ScriptWrappable {
 public:
-    static PassRefPtr<SQLTransaction> create(Database*, PassRefPtr<SQLTransactionCallback>,
-        PassRefPtr<SQLVoidCallback> successCallback, PassRefPtr<SQLTransactionErrorCallback>,
+    static PassRefPtr<SQLTransaction> create(Database*, PassOwnPtr<SQLTransactionCallback>,
+        PassOwnPtr<SQLVoidCallback> successCallback, PassOwnPtr<SQLTransactionErrorCallback>,
         bool readOnly);
 
     void performPendingCallback();
 
     void executeSQL(const String& sqlStatement, const Vector<SQLValue>& arguments,
-        PassRefPtr<SQLStatementCallback>, PassRefPtr<SQLStatementErrorCallback>, ExceptionState&);
+        PassOwnPtr<SQLStatementCallback>, PassOwnPtr<SQLStatementErrorCallback>, ExceptionState&);
 
     Database* database() { return m_database.get(); }
 
+    PassOwnPtr<SQLTransactionErrorCallback> releaseErrorCallback();
+
 private:
-    SQLTransaction(Database*, PassRefPtr<SQLTransactionCallback>,
-        PassRefPtr<SQLVoidCallback> successCallback, PassRefPtr<SQLTransactionErrorCallback>,
+    SQLTransaction(Database*, PassOwnPtr<SQLTransactionCallback>,
+        PassOwnPtr<SQLVoidCallback> successCallback, PassOwnPtr<SQLTransactionErrorCallback>,
         bool readOnly);
 
     void clearCallbackWrappers();