android: optimize atomics routines
    
This patch provides a slightly optimized implementation of
atomic increment/decrement functions by using static inlined
versions of the gcc intrinsics.
Review URL: http://codereview.appspot.com/5498069

git-svn-id: http://skia.googlecode.com/svn/trunk@3012 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed