*** Reason for rollback ***
Rollback global lock because bug (now fixed) was not caused by
threading/concurrency.
*** Original change description ***
Evidence from failures, and inspection of source, leads me to believe
that SharedPreferences has some non-thread-safe paths. As a quick,
brute-force workaround, I'm putting a global lock around our use of it.
This is a bit inefficient, but cases of multiple threads writing to it
should be very rare.
Note, we don't have an explicit test for this (I will think about
finding a way to write one), but the evidence of this failure is that
after some amount of activity in the Email app, we see corrup
... description truncated by g4 rollback ...
Automated import of CL 149140
c2887cd81d