tree c374182ff98f95e2eccba0d279e94195d8385d10
parent a6c443096cc63c31d920a04a22a9378ca25ae48c
author Chia-I Wu <olv@google.com> 1507238681 -0700
committer Chia-I Wu <olv@google.com> 1509033393 -0700

surfaceflinger: make vsync injection more robust

There are more issues than I expected :)

 - no lock to synchronize enable/disable and injection
 - Every time injection is diabled and enabled, a new EventThread is
   created
 - mCallback might be nullptr
 - ENABLE_VSYNC_INJECTIONS/INJECT_VSYNC should require special
   permission
 - MessageQueue::setEventThread must be called from the main thread
 - MessageQueue::setEventThread does not handle EventThread switch
   well

Bug: 65483324
Test: manual
Change-Id: I7d7b98d1f57afc64af0f2065a9bc7c8ad004ca9f