[NUI] AccessibilityCalculateStatesWrapper Missing null check

[Seungkeun Lee]

TizenFX/src/Tizen.NUI/src/public/BaseComponents/ViewAccessibilityWrappers.cs

Lines 95 to 109 in 356b2ee

 private static ulong AccessibilityCalculateStatesWrapper(IntPtr self, ulong initialStates) 
 { 
     View view = GetViewFromRefObject(self); 
     ulong bitMask = 0UL; 
  
     lock (AccessibilityInitialStates) 
     { 
         AccessibilityInitialStates.BitMask = initialStates; 
         bitMask = view.AccessibilityCalculateStates().BitMask; 
         AccessibilityInitialStates.BitMask = 0UL; 
     } 
  
     return bitMask; 
 } 
  

view could be null, but didn't check null