[Toolkit.Graphics] Desktop platform over RDP, Part 1

I have used the same approach as it was for WinRT - the fix was implemented so that the applications will work in emulator. As WinRT emulator works over RDP (it creates second user session on the same machine) - the same approach is applicable to Desktop platform.
Code duplication was slightly reduced while keeping its readability.

When Part 1 will be accepted - proceed to the Part 2 (it will be sent as a separate pull request)