This reverts commit a362c37c8b.
The commit tried to add an unused function that continued our tradition
of not properly waiting for things but instead flooding event loop with
condition checks that delay firing of the event. I think this is a
fundamentally flawed approach. See also checks for
`fire_when_not_visible` in LibCore/EventLoopImplementationUnix.cpp.
Core::deferred_invoke is a way of executing an action after previously
queued events have been processed. It removes the requirement of
having/being a Core::Object subclass in order to defer invocation
through Core::Object::deferred_invoke.
Core::Object::deferred_invoke now delegates to Core::deferred_invoke.
The version with the Object& argument is still present but will be
removed in the following commits.
This commit additionally fixes a new places where the
DeferredInvocationEvent was dispatched to the event loop directly, and
replaces them with the Core::deferred_invoke equivalent.
