Upgrade WX to r74856, mainly to support @2x.

Externals/wxWidgets3/include/wx/windowptr.h

@@ -0,0 +1,63 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        wx/windowptr.h
+// Purpose:     smart pointer for holding wxWindow instances
+// Author:      Vaclav Slavik
+// Created:     2013-09-01
+// Copyright:   (c) 2013 Vaclav Slavik
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_WINDOWPTR_H_
+#define _WX_WINDOWPTR_H_
+
+#include "wx/sharedptr.h"
+
+// ----------------------------------------------------------------------------
+// wxWindowPtr: A smart pointer with correct wxWindow destruction.
+// ----------------------------------------------------------------------------
+
+namespace wxPrivate
+{
+
+struct wxWindowDeleter
+{
+    void operator()(wxWindow *win)
+    {
+        win->Destroy();
+    }
+};
+
+} // namespace wxPrivate
+
+template<typename T>
+class wxWindowPtr : public wxSharedPtr<T>
+{
+public:
+    typedef T element_type;
+
+    wxEXPLICIT wxWindowPtr(element_type* win)
+        : wxSharedPtr<T>(win, wxPrivate::wxWindowDeleter())
+    {
+    }
+
+    wxWindowPtr() {}
+    wxWindowPtr(const wxWindowPtr& tocopy) : wxSharedPtr<T>(tocopy) {}
+
+    wxWindowPtr& operator=(const wxWindowPtr& tocopy)
+    {
+        wxSharedPtr<T>::operator=(tocopy);
+        return *this;
+    }
+
+    wxWindowPtr& operator=(element_type* win)
+    {
+        return operator=(wxWindowPtr(win));
+    }
+
+    void reset(T* ptr = NULL)
+    {
+        wxSharedPtr<T>::reset(ptr, wxPrivate::wxWindowDeleter());
+    }
+};
+
+#endif // _WX_WINDOWPTR_H_