Use wxDELETE() and wxDELETEA() when possible.

Use wxDELETE[A]() functions which automatically NULL out their arguments after
deleting them instead of doing it manually.

Closes #9685.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64656 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/os2/bitmap.cpp

@@ -84,11 +84,7 @@ void wxBitmapRefData::Free()
             wxLogLastError(wxT("GpiDeleteBitmap(hbitmap)"));
         }
     }
-    if (m_pBitmapMask)
-    {
-        delete m_pBitmapMask;
-        m_pBitmapMask = NULL;
-    }
+    wxDELETE(m_pBitmapMask);
 } // end of wxBitmapRefData::Free
 
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