AtomicNumber should make dealing with atomic counters easier. This is not the
case with size_t, as we cannot properly use the Increment() method for negative
numbers.
With this CL we can use AtomicNumber<size_t> and have proper decrements.
R=jochen@chromium.org
Review-Url: https://codereview.chromium.org/2215693002
Cr-Commit-Position: refs/heads/master@{#38407}
atomic-utils.h only uses functionality from base/, and also by moving it into
base/, code outside of v8_base can benefit from it.
BUG=v8:4991
LOG=n
Review-Url: https://codereview.chromium.org/1954603002
Cr-Commit-Position: refs/heads/master@{#36114}