Bug 1157784. Add missing DeleteCriticalSection

widget/windows/nsWindow.cpp

@@ -441,6 +441,7 @@ nsWindow::~nsWindow()
       sIsOleInitialized = FALSE;
     }
   }
+  ::DeleteCriticalSection(&mPresentLock);
 
   NS_IF_RELEASE(mNativeDragTarget);
 }