Added WebRTC audio quality test using fake device; improved fake device

Added WebRTC audio quality test using fake device; improved fake device

This finally adds a end-to-end WebRTC audio quality test which includes
getUserMedia and the capture path (except, obviously, the os-specific
code which actually interacts with the capture device etc).

This patch also makes the audio input device generic. It will now
convert its input .wav file to suit the audio bus. I had to do this
because the PESQ tests require files to be mono, 16-bit and so on.

BUG=446859
Committed: https://crrev.com/b0a18bb4d74babb14f98808f0270c540cc2efd13
Cr-Commit-Position: refs/heads/master@{#310736}

[phoglund_chromium, 2015-01-07 15:16:25]

phoglund@chromium.org changed reviewers:
+ henrika@chromium.org

[phoglund_chromium, 2015-01-07 15:16:26]

https://codereview.chromium.org/831693004/diff/1/chrome/browser/media/chrome_...
File chrome/browser/media/chrome_webrtc_audio_quality_browsertest.cc (right):

https://codereview.chromium.org/831693004/diff/1/chrome/browser/media/chrome_...
chrome/browser/media/chrome_webrtc_audio_quality_browsertest.cc:680: // Note:
the sound clip is about 13 seconds: record for 20 seconds to get some
This is because I added 3 seconds of silence to the ref file for this test.

[henrika (OOO until Aug 14), 2015-01-07 15:20:16]

LGTM % (the fact that I might not understand all the details in the actual
test).

[phoglund_chromium, 2015-01-08 15:22:04]

The CQ bit was checked by phoglund@chromium.org

[commit-bot: I haz the power, 2015-01-08 15:22:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/831693004/1

[commit-bot: I haz the power, 2015-01-08 15:29:32]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-08 15:29:33]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[phoglund_chromium, 2015-01-08 15:51:08]

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

[phoglund_chromium, 2015-01-08 15:51:08]

phoglund@chromium.org changed required reviewers:
+ dalecurtis@chromium.org

[phoglund_chromium, 2015-01-08 15:51:08]

Dale: need approval for the comment change in media_switches (context: I made
the fake device use AudioConverter, so it can now accept pretty much any kind of
.wav file).

[DaleCurtis, 2015-01-08 22:04:53]

lgtm

[phoglund_chromium, 2015-01-09 07:41:55]

The CQ bit was checked by phoglund@chromium.org

[commit-bot: I haz the power, 2015-01-09 07:42:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/831693004/1

[commit-bot: I haz the power, 2015-01-09 08:14:48]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-09 08:15:45]

Patchset 1 (id:??) landed as
https://crrev.com/b0a18bb4d74babb14f98808f0270c540cc2efd13
Cr-Commit-Position: refs/heads/master@{#310736}