This commit introduces new mechanisms to solve some issues with full screen support:
1. Full screen covers disappear when its caller disappears (e.g. when it
is an event in a lazy stack, and an orientation change causes the
view to disappear along with the full screen cover)
2. There are no mechanisms for views to determine whether they are being
presented under a full screen cover or not, and whether the device is
in full screen mode or not.
The commit overcomes the above limitations through the following:
1. A full screen cover on `ContentView` that can be accessed by any view
when calling `present(fullScreenItem)`
2. A new `damus_full_screen_cover` view modifier that automatically
tracks whether a device is in full screen mode or not, and allows
any descendant view in its hierarchy to introspect on which view
layer it is being presented in.
This commit lays a foundation that will later become important for
improving video coordination.
Signed-off-by: Daniel D’Aquino <daniel@daquino.me>
1bc660c9cd