Implement native tab art for wxAUI in wxGTK.

Use native wxAuiTabArt implementation in wxGTK, it better conforms to the
system style.

Closes #14098.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71002 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/aui/tabartgtk.h

@@ -0,0 +1,56 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        include/wx/aui/tabartgtk.h
+// Purpose:     declaration of the wxAuiGTKTabArt
+// Author:      Jens Lody and Teodor Petrov
+// Modified by:
+// Created:     2012-03-23
+// RCS-ID:      $Id:$
+// Copyright:   (c) 2012 Jens Lody <jens@codeblocks.org>
+//                  and Teodor Petrov
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_AUI_TABARTGTK_H_
+#define _WX_AUI_TABARTGTK_H_
+
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+#include "wx/defs.h"
+
+#if wxUSE_AUI
+
+#include "wx/aui/tabart.h"
+#include "wx/gdicmn.h"
+
+class wxWindow;
+class wxDC;
+
+class WXDLLIMPEXP_AUI wxAuiGtkTabArt : public wxAuiGenericTabArt
+{
+public:
+    wxAuiGtkTabArt();
+
+    virtual wxAuiTabArt* Clone();
+    virtual void DrawBackground(wxDC& dc, wxWindow* wnd, const wxRect& rect);
+    virtual void DrawTab(wxDC& dc,
+                         wxWindow* wnd,
+                         const wxAuiNotebookPage& page,
+                         const wxRect& in_rect,
+                         int close_button_state,
+                         wxRect* out_tab_rect,
+                         wxRect* out_button_rect,
+                         int* x_extent);
+    void DrawButton(wxDC& dc, wxWindow* wnd, const wxRect& in_rect, int bitmap_id,
+                    int button_state, int orientation, wxRect* out_rect);
+    int GetBestTabCtrlSize(wxWindow* wnd, const wxAuiNotebookPageArray& pages,
+                            const wxSize& required_bmp_size);
+    virtual wxSize GetTabSize(wxDC& dc, wxWindow* wnd, const wxString& caption,
+                              const wxBitmap& bitmap, bool active,
+                              int close_button_state, int* x_extent);
+};
+
+#endif  // wxUSE_AUI
+
+#endif // _WX_AUI_TABARTGTK_H_