Don't allow CoreAudioUtil::IsSupported() to reinitialize COM.

Don't allow CoreAudioUtil::IsSupported() to reinitialize COM.

I introduced this change in http://crrev.com/324246 but I now
think it's incorrect based on the fact that the UI thread
should already have COM initialized.

BUG=422522
TEST=audio plays

Committed: https://crrev.com/84c468567142e212b6c07ffc12458d9e5a797192
Cr-Commit-Position: refs/heads/master@{#327244}

[DaleCurtis, 2015-04-28 01:56:43]

dalecurtis@chromium.org changed reviewers:
+ tommi@chromium.org

[tommi (sloooow) - chröme, 2015-04-28 06:54:49]

The CQ bit was checked by tommi@chromium.org

[tommi (sloooow) - chröme, 2015-04-28 06:54:50]

lgtm

[commit-bot: I haz the power, 2015-04-28 06:54:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1103383003/1

[tommi (sloooow) - chröme, 2015-04-28 06:56:23]

Thanks for fixing. I guess I could have told you about the problems the previous
change would have caused a couple of weeks ago, but live and learn :)

[commit-bot: I haz the power, 2015-04-28 08:03:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-28 08:04:11]

Patchset 1 (id:??) landed as
https://crrev.com/84c468567142e212b6c07ffc12458d9e5a797192
Cr-Commit-Position: refs/heads/master@{#327244}