remove WXWIN_COMPATIBILITY_2_6, add WXWIN_COMPATIBILITY_3_0

closes #15792

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75532 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/filehistory.h

@@ -60,11 +60,6 @@ public:
     void SetBaseId(wxWindowID baseId) { m_idBase = baseId; }
     wxWindowID GetBaseId() const { return m_idBase; }
 
-#if WXWIN_COMPATIBILITY_2_6
-    // deprecated, use GetCount() instead
-    wxDEPRECATED( size_t GetNoHistoryFiles() const );
-#endif // WXWIN_COMPATIBILITY_2_6
-
 protected:
     // Last n files
     wxArrayString     m_fileHistory;
@@ -86,14 +81,6 @@ private:
     wxDECLARE_NO_COPY_CLASS(wxFileHistoryBase);
 };
 
-#if WXWIN_COMPATIBILITY_2_6
-inline size_t wxFileHistoryBase::GetNoHistoryFiles() const
-{
-    return m_fileHistory.GetCount();
-}
-#endif // WXWIN_COMPATIBILITY_2_6
-
-
 #if defined(__WXGTK20__)
     #include "wx/gtk/filehistory.h"
 #else