Switch wtf/SpinLock to std::atomic
Tsan identified a racy read in the existing spin lock loop.
Tsan is correct in the absolute sense, even though the read is
safe in practice. However, the architectures we support might
change, or the behavior of the compiler might change, so the
the best fix is to just use the proper std::atomic type,
because that is guaranteed to always be safe. And the compiled
code should be effectively unchanged.
BUG=556469
NOTRY=True
Review URL: https://codereview.chromium.org/1463683002
Cr-Commit-Position: refs/heads/master@{#363347}
9 files changed
