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/wincmn.cpp

@@ -364,8 +364,7 @@ wxWindowBase::~wxWindowBase()
         // This removes any dangling pointers to this window in other windows'
         // constraintsInvolvedIn lists.
         UnsetConstraints(m_constraints);
-        delete m_constraints;
-        m_constraints = NULL;
+        wxDELETE(m_constraints);
     }
 #endif // wxUSE_CONSTRAINTS
 
@@ -1254,8 +1253,7 @@ wxEvtHandler *wxWindowBase::PopEventHandler(bool deleteHandler)
 
     if ( deleteHandler )
     {
-        delete firstHandler;
-        firstHandler = NULL;
+        wxDELETE(firstHandler);
     }
 
     return firstHandler;
@@ -2076,8 +2074,7 @@ void wxWindowBase::DeleteRelatedConstraints()
             node = next;
         }
 
-        delete m_constraintsInvolvedIn;
-        m_constraintsInvolvedIn = NULL;
+        wxDELETE(m_constraintsInvolvedIn);
     }
 }