Refactor: extra wxStaticText auto-resizing code from wxMSW to common.

This will allow its reuse in wxGenericStaticText and maybe other ports that
need it in the future.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78061 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/stattext.h

@@ -78,6 +78,10 @@ protected:      // functions required for wxST_ELLIPSIZE_* support
     // but may contain the mnemonic characters.
     virtual void DoSetLabel(const wxString& WXUNUSED(str)) { }
 
+    // Update the current size to match the best size unless wxST_NO_AUTORESIZE
+    // style is explicitly used.
+    void AutoResizeIfNecessary();
+
 private:
     wxDECLARE_NO_COPY_CLASS(wxStaticTextBase);
 };