Fix android build issues with atomics

Uses inline methods for sk_atomic_inc/add/dec instead of #define.
Since those methods are declared as static in SkThread.h, they need
a definition or else the compiler generates an error. Also corrects
a typo.

BUG=skia:
R=djsollen@google.com, bungeman@google.com, bsalomon@google.com

Author: cdalton@nvidia.com

Review URL: https://codereview.chromium.org/148113010

git-svn-id: http://skia.googlecode.com/svn/trunk@13360 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed