Remove dependency of SSLPlatformKeyTaskRunner on single-threaded SequencedWorkerPool.
Use a base::Thread bound to a LazyInstance (so it's never joined) instead,
keeping CONTINUE_ON_SHUTDOWN semantics.
Make the API explicitly use SingleThreadTaskRunner for both SSLPlatformKeyTaskRunner
and ThreadedSSLPrivateKey as they appear to have a hard requirement on this being
the case: https://codereview.chromium.org/2077413009/#msg16
Explicitly document that the exposed SingleThreadTaskRunner has CONTINUE_ON_SHUTDOWN
semantics as this is also a critical requirement.
BUG=622400
Review-Url: https://codereview.chromium.org/2103883004
Cr-Commit-Position: refs/heads/master@{#409668}
4 files changed
