Make DoGetBestSize cache the value of GetSize() the first time it is called

for the case when the control is a regular window with no children.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@26583 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/window.h

@@ -1077,6 +1077,9 @@ protected:
 #if wxUSE_ACCESSIBILITY
     wxAccessible*       m_accessible;
 #endif
+    // Best size for controls which fail to implement DoGetBestSize()
+    wxSize              m_bestSize;
+
     // Virtual size (scrolling)
     wxSize                m_virtualSize;