hwc: clean up overlay for external from the draw thread only

Cleanup overlay for external from the draw thread. If done from the uevent
thread, its possible that the object being used by draw thread is deleted by
uevent thread.

This also removes unnecessary side-effects where libexternal sets states in
hwc, whereas, it could be set from hwc itself. There should be no need for
libexternal to modify states in hwc.

Bug: 7335863 (partial fix)
Change-Id: If07483e640abae2ced2418e0d5c8f278f8c6ec33
Signed-off-by: Iliyan Malchev <malchev@google.com>
5 files changed