Safe and reliable fix for 2 race conditions.
(We may want to revisit the issue later, implementing more performant one...)

BUG=107933
TEST=Everything should work, and there would be no more crashes in AudioDevice.

Review URL: http://codereview.chromium.org/9112029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@117464 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed