Currently, the dependencies between foreign-toplevel[-internal],
ext-foreign, and wlr-foreign are cyclical and a bit complex.
I suggest we reorganize it into a simpler hierarchy:
foreign-toplevel/
-> foreign.c/h
-> (depends on) ext-foreign.c/h
-> (depends on) wlr-foreign.c/h
The refactored code is smaller and (IMO) easier to follow.
In detail:
- Add include/foreign-toplevel folder mirroring src/foreign-toplevel
- Split foreign-toplevel-internal.h to ext-foreign.h and wlr-foreign.h
- Eliminate ext-/wlr-foreign.c -> foreign.c reverse dependencies
(including internal signals and foreign_request* functions)
- Make struct foreign_toplevel private to foreign.c
Lightly tested with qmpanel (which uses wlr-foreign-toplevel).
v2: reorder foreign-toplevel internal API funcs
If the handle gets destroyed from the wlroots side before the view
is destroyed, the internal signals (emitted from the view) are not
disconnected and will assert() if invoked.
This fixes a bug that output_enter events are not sent when a Slack
window running in background is re-mapped, which caused missing taskbar
items in Waybar when it's configured to show windows per output.
