Regarding didComplete():
When a WebInputStream is destroyed, the thread of execution will wait in
SharedSession::removeTask() until the task is no longer present in the
list of all active tasks. If multiple threads are all waiting in
removeTask(), then all of those threads should wake when the set of
active tasks changes. Waking only a single thread may result in
deadlocks, as that thread's task may not have completed successfully.
Then, the thread that woke up will be forced to sleep again and may not
get another chance to wake.
Regarding didBecomeInvalid():
Normally, didBecomeInvalid() will only be called after the
SharedSession's destructor. If the destructor is running, we may assume
that no other thread can access the SharedSession, so using notify_one()
in didBecomeInvalid() should be sufficient to wake up the destructor's
thread. However, there's a chance that the NSURLSession may be
invalidated unexpectedly (i.e. before the SharedSession's destructor
runs), in which case there may still be threads waiting in removeTask().
In this scenario we need to notify_all() so that all waiting threads are
able to wake and make progress.
This is a different approach to the change introduced in
04f87320d5.
Instead of completely recreating the window, we now just update the
window's style flags. This should ensure that window and component focus
are preserved.
This follows on from the work in
3e70c37ce3.
The previous patch had the intended effect as long as the peer was
recreated after entering kiosk mode. However, for windows initially
created with non-native titlebars, attempting to disable the titlebar
would have no effect.
We now check whether the native style flags would need to change as a
result of changing kiosk mode, and recreate the peer if necessary.
ObjCClass doesn't have other virtual methods; it is not intended to be
used as an interface or dynamic type. Removing the virtual destructor
is intended to promote composition over inheritance when using this
type.
