typedef OutputDevice as RenderContext to pass to Paint methods

Change-Id: I858c0c51fc0892ea81ac39f69aff7d401a25184b
diff --git a/include/vcl/window.hxx b/include/vcl/window.hxx
index 3134e50..1a1aef9 100644
--- a/include/vcl/window.hxx
+++ b/include/vcl/window.hxx
@@ -375,6 +375,8 @@ struct WindowResHeader

namespace vcl {

typedef OutputDevice RenderContext;

class VCL_DLLPUBLIC Window : public ::OutputDevice, public Resource
{
    friend class ::vcl::Cursor;