Oilpan: Prepare to move AbstractSQLTransaction and SQLTransaction to Oilpan heap.

Source/modules/webdatabase/AbstractSQLTransaction.h

Index: Source/modules/webdatabase/AbstractSQLTransaction.h
diff --git a/Source/modules/webdatabase/AbstractSQLTransaction.h b/Source/modules/webdatabase/AbstractSQLTransaction.h
index ba8e9997e5d7971df8c4c82f53d9a52616c1532a..ba823b985fe262ca4e4db4542796037451d2faed 100644
--- a/Source/modules/webdatabase/AbstractSQLTransaction.h
+++ b/Source/modules/webdatabase/AbstractSQLTransaction.h
@@ -26,6 +26,7 @@
 #ifndef AbstractSQLTransaction_h
 #define AbstractSQLTransaction_h
 
+#include "heap/Handle.h"
 #include "modules/webdatabase/SQLTransactionState.h"
 #include "wtf/ThreadSafeRefCounted.h"
 
@@ -33,9 +34,10 @@ namespace WebCore {
 
 class AbstractSQLTransactionBackend;
 
-class AbstractSQLTransaction : public ThreadSafeRefCounted<AbstractSQLTransaction> {
+class AbstractSQLTransaction : public ThreadSafeRefCountedWillBeGarbageCollectedFinalized<AbstractSQLTransaction> {
 public:
     virtual ~AbstractSQLTransaction() { }
+    virtual void trace(Visitor*) = 0;
 
     virtual void requestTransitToState(SQLTransactionState) = 0;