Add RAII wrapper for GTKDisableEvents/GTKEnableEvents() calls

Ensure GTKEnableEvents() is called automatically on scope exit whenever
GTKDisableEvents() is called.

This fixes a couple of potential bugs where GTKEnableEvents() could be not
called if wxCHECK() condition failed and makes the code shorter and safer.

include/wx/gtk/private/eventsdisabler.h

@@ -0,0 +1,41 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/gtk/private/eventsdisabler.h
+// Purpose:     Helper for temporarily disabling events.
+// Author:      Vadim Zeitlin
+// Created:     2016-02-06
+// Copyright:   (c) 2016 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _GTK_PRIVATE_EVENTSDISABLER_H_
+#define _GTK_PRIVATE_EVENTSDISABLER_H_
+
+// ----------------------------------------------------------------------------
+// wxGtkEventsDisabler: calls GTKDisableEvents() and GTKEnableEvents() in dtor.
+// ----------------------------------------------------------------------------
+
+// Template parameter T must be a wxGTK class providing the required methods,
+// e.g. wxCheckBox, wxChoice, ...
+template <typename T>
+class wxGtkEventsDisabler
+{
+public:
+    // Disable the events for the specified (non-NULL, having lifetime greater
+    // than ours) window for the lifetime of this object.
+    explicit wxGtkEventsDisabler(T* win) : m_win(win)
+    {
+        m_win->GTKDisableEvents();
+    }
+
+    ~wxGtkEventsDisabler()
+    {
+        m_win->GTKEnableEvents();
+    }
+
+private:
+    T* const m_win;
+
+    wxDECLARE_NO_COPY_TEMPLATE_CLASS(wxGtkEventsDisabler, T);
+};
+
+#endif // _GTK_PRIVATE_EVENTSDISABLER_H_

include/wx/gtk/tglbtn.h

@@ -54,10 +54,10 @@ public:
     static wxVisualAttributes
     GetClassDefaultAttributes(wxWindowVariant variant = wxWINDOW_VARIANT_NORMAL);
 
-protected:
     void GTKDisableEvents();
     void GTKEnableEvents();
 
+protected:
     virtual wxSize DoGetBestSize() const wxOVERRIDE;
     virtual void DoApplyWidgetStyle(GtkRcStyle *style) wxOVERRIDE;