Oilpan: IDBCursor should be detached from IDBRequest when the IDBRequest stops

Source/platform/LifecycleObserver.h

Index: Source/platform/LifecycleObserver.h
diff --git a/Source/platform/LifecycleObserver.h b/Source/platform/LifecycleObserver.h
index 2f6765e24d5b1d85451f707ad7589e8c7d5afb15..70eb168fe8c7007a55387889345dcfcd2746ac6a 100644
--- a/Source/platform/LifecycleObserver.h
+++ b/Source/platform/LifecycleObserver.h
@@ -56,9 +56,9 @@ public:
         observeContext(0);
     }
 
+    virtual void contextWillBeDestroyed() { }
     virtual void contextDestroyed() { m_lifecycleContext = 0; }
 
-
     Context* lifecycleContext() const { return m_lifecycleContext; }
     Type observerType() const { return m_observerType; }