This is inspired by 98892391d7 where the usage of
`g_signal_handler_disconnect()` without resetting the corresponding
handler id later resulted in a bug. Using `g_clear_signal_handler()`
makes sure we avoid similar bugs and is almost always the better
alternative. We use it for new code, let's clean up the old code to
also use it.
A further benefit is that it can get called even if the passed id is
0, allowing us to remove a lot of now unnessecary checks, and the fact
that `g_clear_signal_handler()` checks for the right type size, forcing us
to clean up all places where we used `guint` instead of `gulong`.
No functional changes intended here and all changes should be trivial,
thus bundled in one big commit.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/940
This adds the required bits to wayland surfaces and ties them up
to the compositor parts.
It is based on and very similar in nature to buffer transforms.
From the specification:
> The global interface exposing surface cropping and scaling
> capabilities is used to instantiate an interface extension for a
> wl_surface object. This extended interface will then allow cropping
> and scaling the surface contents, effectively disconnecting the
> direct relationship between the buffer and the surface size.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/323
