Use default constructors for wxSize/Point/Rect.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@31904 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/renderg.cpp

@@ -355,7 +355,7 @@ wxRendererGeneric::DrawComboBoxDropButton(wxWindow *win,
 
     wxPoint pt[3] =
     {
-        wxPoint(0, 0),
+        wxPoint(),
         wxPoint(rect.width, 0),
         wxPoint(rect.width/2, rect.height - 2)
     };