Window embedding API
I have a trouble porting application functionality to Wayland. The application has web-based features and uses webkit2gtk while itself is not written in gtk. It does so with window embedding, but I don't see equivalent API in Wayland. I heard I can create a nested compositor, but I fail to find a library that would allow me doing that in a reasonable amount of code. Implementing low-level things like mapping input/output/keyboard layout/keyboard/entire xdg-shell/etc is absolutely doesn't worth the effort (especially given that Wayland is only 7% of 2% of the application userbase currently and all other platforms allow to embed system-provided webview with a little amount of code, like in 3 lines using toolkit-provided API and native window handle).
I believe this is an essential problem as not every toolkit has things like webview and cross-toolkit interability is a must therefore.