Hey, i got some free time around now and my friend pointed me to this post and i found it quite interestring.
Before reading the rest of the post, since it wasn't completed and it was a few months, I decided to try it and got to a quite different apporach.
I endeded up altering the CMake builf in order to generate WinRT components that we can use from other UWP code. That way we shouldn't have too many problems and we (probably) can init the D3D context and pass it to Dolphin easily. I've got various libraries to build, but there's various bugs as lots of parts in the toolchain assumes Win32 is WinRT. I'm getting them fixed. The Android target did give me lots of helpful hints. I think i will add another platform to the CMake file to target WinRT. I'm going to clean it up and publish it on GitHub when i got a better picture overall.
(Note: WinRT means Windows Runtime Platform, not to the Tablet OS.)
Also:
Getting the emulator core working is far more difficult than the UI.
It will _not_ run great. Dolphin only uses 2 cores, and Xbox One uses low power netbook Jaguar cores which will not help dolphin work at full speed. This can't be changed unless a big rewrite to Dolphin's core implementing some sort of micro-parallelism like Firefox did with their new Servo engine that was entirely rewriten in Rust. And i'm not sure if this is even possible or would benefit anything on it. And i really don't see that happening.