After fixing b/16874785.
This reverts commit f010a05c7e.
Original comment, which actually describes the effect of this:
Change the mExtras field in Binder.h to be a stdatomic.h atomic
value, and replace references to it with proper stdatomic.h calls.
This removes one of a small number of remaining 64 bit
android_atomic references. It also replaces the erroneously
non-atomic read accesses to mExtras.
It would be better if this used the C++11 <atomic> facility,
but we don't quite have that yet.
Fixes
Bug:16513433
Change-Id: I1645ca5d6f60595bf5d388913665ce4b8780b26d
(cherry picked from commit 3effababf2)