Use UNLIKELY in spinLockLock to denote contention as the unlikely case.

This ensures that the machine jump instruction is not taken for the common case
of no contention.

Review URL: https://codereview.chromium.org/131023005

git-svn-id: svn://svn.chromium.org/blink/trunk@165477 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[webcrypto] Delete some deprecated code.

BUG=245025
TBR=abarth

Review URL: https://codereview.chromium.org/141073008

git-svn-id: svn://svn.chromium.org/blink/trunk@165478 bbb929c8-8fbe-4397-9dbb-9b2b20218538