Content type protocol
This is just an idea, not sure it's a good one yet.
Add a protocol to allow clients to specify the content type of their surface. Example possible content types: none, picture, video, game.
Use-cases:
- Automatically set the HDMI "content type" property. This is used by screens to decide whether to apply filters to "improve" the content.
- Synchronize the cursor with the game updates (required for VRR)