Simplify WebRTC DelayMetrics query in MediaStreamAudioProcessor

Simplify WebRTC DelayMetrics query in MediaStreamAudioProcessor

As of webrtc roll https://chromium.googlesource.com/chromium/src/+/724ab4480d4af0c4a64752078a7cd5046782789c
a longer aggregation window is used and we can now match it to simplify the query.

BUG=450193
TESTED=locally on Mac

Committed: https://crrev.com/971f184b39b257dd7cf053a8711faf1ec977035a
Cr-Commit-Position: refs/heads/master@{#319564}

[bjornv, 2015-03-07 09:57:02]

bjornv@chromium.org changed reviewers:
+ perkj@chromium.org

[bjornv, 2015-03-07 10:02:18]

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

[bjornv, 2015-03-07 10:05:09]

Tommi: added you as a reviewer since Per is ooo until 3/16. Per reviewed an
earlier CL for this, but I'd like to get this in before he returns. Let me know
if you think Per should take a look as well before a commit (if you approve that
is).

[tommi (sloooow) - chröme, 2015-03-07 11:23:41]

The CQ bit was checked by tommi@chromium.org

[tommi (sloooow) - chröme, 2015-03-07 11:23:42]

lgtm

[commit-bot: I haz the power, 2015-03-07 11:23:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/982333002/1

[commit-bot: I haz the power, 2015-03-07 23:02:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-07 23:03:31]

Patchset 1 (id:??) landed as
https://crrev.com/971f184b39b257dd7cf053a8711faf1ec977035a
Cr-Commit-Position: refs/heads/master@{#319564}