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/common/docview.cpp

@@ -1953,8 +1953,7 @@ bool wxDocChildFrameAnyBase::CloseView(wxCloseEvent& event)
         // deleted directly not by us as indicated by its doc child frame
         // pointer still being set
         m_childView->SetDocChildFrame(NULL);
-        delete m_childView;
-        m_childView = NULL;
+        wxDELETE(m_childView);
     }
 
     m_childDocument = NULL;