Move wxTopLevelWindow::SetShape() down to wxNonOwnedWindow.

Also add wxNonOwnedWindow for wxMSW (which previously simply typedef'd it to
wxWindow) and document this class now that it provides some user-visible
functionality.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69364 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/nonownedwnd.h

@@ -0,0 +1,36 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        interface/wx/nonownedwnd.h
+// Purpose:     wxNonOwnedWindow class documentation
+// Author:      Vadim Zeitlin
+// Created:     2011-10-09
+// RCS-ID:      $Id$
+// Copyright:   (c) 2011 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+/**
+    Common base class for all non-child windows.
+
+    This is the common base class of wxTopLevelWindow and wxPopupWindow and is
+    not used directly.
+
+    Currently the only additional functionality it provides, compared to base
+    wxWindow class, is the ability to set the window shape.
+
+    @since 2.9.3
+ */
+class wxNonOwnedWindow : public wxWindow
+{
+public:
+    /**
+        If the platform supports it, sets the shape of the window to that
+        depicted by @a region. The system will not display or respond to any
+        mouse event for the pixels that lie outside of the region. To reset the
+        window to the normal rectangular shape simply call SetShape() again with
+        an empty wxRegion. Returns @true if the operation is successful.
+
+        This method is available in this class only since wxWidgets 2.9.3,
+        previous versions only provided it in wxTopLevelWindow.
+    */
+    virtual bool SetShape(const wxRegion& region);
+};