Use SkAtomics_sync on Android

Use SkAtomics_sync on Android

Every doc I've found about using Android's atomics says, "stop".

"* A handful of basic atomic operations.  The appropriate pthread
 * functions should be used instead of these whenever possible."

"... we recommend stopping from using these functions entirely. Very fortunately, GCC provides handy intrinsics functions that work with very reasonable performance and always provide a full barrier."

As far as I can tell, there's no code generation change here: both the __sync atomics and the android_ atomics use full memory barriers.  (And now with this all unified, it'll be easier to get the real wins by switching everything to __atomic atomics, which are like __sync atomics but allow control over memory barriers.)

BUG=skia:

Committed: http://code.google.com/p/skia/source/detail?r=14896

[djsollen, 2014-05-27 15:32:54]

lgtm

[mtklein, 2014-05-27 15:34:01]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-05-27 15:34:08]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/mtklein@chromium.org/305593002/1

[commit-bot: I haz the power, 2014-05-27 15:34:13]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-05-27 15:34:13]

Presubmit check for 305593002-1 failed and returned exit status 1.

Running presubmit commit checks ...

** Presubmit ERRORS **
Since the CL is editing public API, you must have an LGTM from one of:
('reed@chromium.org', 'reed@google.com', 'bsalomon@chromium.org',
'bsalomon@google.com')

Was the presubmit check useful? If not, run "git cl presubmit -v"
to figure out which PRESUBMIT.py was run, then run git blame
on the file to figure out who to ask for help.

[mtklein, 2014-05-27 15:37:55]

+reed for include, still no API changes.

[mtklein, 2014-05-27 15:38:27]

actually +reed for include.  No API changes.

[reed1, 2014-05-27 15:38:51]

lgtm -- +1 for deleting lines

[mtklein, 2014-05-27 15:50:25]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-05-27 15:50:39]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/mtklein@chromium.org/305593002/1

[commit-bot: I haz the power, 2014-05-27 15:55:38]

Change committed as 14896