Fixes#2303, as well as a crash.
To replicate the crash:
* Have multiple outputs
* In config: for_window [<criteria>] workspace foo
* Also in config: workspace foo output <left-output-name>
* Focus the right output, and ensure workspace foo doesn't exist
* Launch the app that triggers the criteria
When the view maps, it calls workspace_switch which calls
send_set_focus which calls cursor_send_pointer_motion which calls
transaction_commit_dirty. This call to transaction_commit_dirty is not
meant to happen at this time because the tree isn't guaranteed to be in
a consistent state, but I'm not sure how exactly this leads to the crash
or render issues.
In this case the transaction is already committed by the view
implementation's handle_map function. So the solution is to remove it
from cursor_send_pointer_motion and add it to the other functions in
cursor.c which call cursor_send_pointer_motion.
This allows to send wl_pointer.enter when switching between views
in a split/tabbed layout for instance. This (1) updates the cursor
image accordingly (2) makes it unnecessary to move the mouse before
scrolling. It's harmless to always call cursor_send_pointer_motion
because in case the focused surface hasn't changed this is a no-op.
The `last_focus != NULL` condition is required otherwise
cursor_send_pointer_motion will crash when sway starts up (the
sway_output doesn't yet have a workspace).
When an xwayland view is mapped, the IPC urgent event was being sent on
every surface commit.
I had intentionally ommitted the check because I figured an urgent
surface could update its urgent timestamp by sending urgent a second
time. But that's not how it works in xwayland's case, and it makes for
more complicated code.