Added native wxInfoBar implementation for wxGTK.

Straightforward implementation of wxInfoBar using GtkInfoBar widget available
in GTK+ 2.18.

Some side effects of this change:

- Rename wxInfoBar version in wx/generic/infobar.h to wxInfoBarGeneric and
  define wxInfoBar in wx/infobar.h.
- Also change default value of flags argument to ShowMessage() to
  wxICON_INFORMATION from wxICON_NONE as the default colour for wxICON_NONE
  messages is surprisingly ugly in GTK native version.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62276 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/infobar.h

@@ -0,0 +1,64 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/gtk/infobar.h
+// Purpose:     native implementation of wxInfoBar for GTK+ 2.18 and later
+// Author:      Vadim Zeitlin
+// Created:     2009-09-26
+// RCS-ID:      $Id: wxhead.h,v 1.11 2009-06-29 10:23:04 zeitlin Exp $
+// Copyright:   (c) 2009 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_GTK_INFOBAR_H_
+#define _WX_GTK_INFOBAR_H_
+
+#include "wx/generic/infobar.h"
+
+// ----------------------------------------------------------------------------
+// wxInfoBar for GTK+
+// ----------------------------------------------------------------------------
+
+// notice that the native GTK+ implementation is only available since
+// (relatively recent) 2.18 so we inherit from the generic one to be able to
+// fall back to it if GTK+ version is determined to be too old during run-time
+class WXDLLIMPEXP_ADV wxInfoBar : public wxInfoBarGeneric
+{
+public:
+    wxInfoBar() { Init(); }
+
+    wxInfoBar(wxWindow *parent, wxWindowID winid = wxID_ANY)
+    {
+        Init();
+        Create(parent, winid);
+    }
+
+    bool Create(wxWindow *parent, wxWindowID winid = wxID_ANY);
+
+    virtual ~wxInfoBar();
+
+    // implement base class methods
+    // ----------------------------
+
+    virtual void ShowMessage(const wxString& msg,
+                             int flags = wxICON_INFORMATION);
+
+    virtual void AddButton(wxWindowID btnid,
+                           const wxString& label = wxString());
+
+    // implementation only
+    // -------------------
+
+    void GTKResponse(int btnid);
+
+protected:
+    virtual bool GTKShouldConnectSizeRequest() const { return false; }
+
+private:
+    void Init() { m_label = NULL; }
+
+    GtkWidget *m_label;
+
+    wxDECLARE_NO_COPY_CLASS(wxInfoBar);
+};
+
+#endif // _WX_GTK_INFOBAR_H_
+