Fixed incorrect handling of timestamps in video quality test

Fixed incorrect handling of timestamps in video quality test

* Both timestamps must be unwrapped before comparing
* rtp timestamp delta must be subtracted before unwrapping

BUG=webrtc:5637, webrtc:5537
Committed: https://crrev.com/16daaa5a407e0b7c6918ee0974d1b00c5a7f0db3
Cr-Commit-Position: refs/heads/master@{#11926}

[sprang_webrtc, 2016-03-08 14:39:14]

sprang@webrtc.org changed reviewers:
+ pbos@webrtc.org

[pbos-webrtc, 2016-03-08 22:40:47]

lgtm

[sprang_webrtc, 2016-03-09 08:42:11]

The CQ bit was checked by sprang@webrtc.org

[commit-bot: I haz the power, 2016-03-09 08:42:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1774123003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1774123003/1

[commit-bot: I haz the power, 2016-03-09 09:30:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-09 09:41:01]

Description was changed from

==========
Fixed incorrect handling of timestamps in video quality test

* Both timestamps must be unwrapped before comparing
* rtp timestamp delta must be subtracted before unwrapping

BUG=webrtc:5637, webrtc:5537
==========

to

==========
Fixed incorrect handling of timestamps in video quality test

* Both timestamps must be unwrapped before comparing
* rtp timestamp delta must be subtracted before unwrapping

BUG=webrtc:5637, webrtc:5537

Committed: https://crrev.com/16daaa5a407e0b7c6918ee0974d1b00c5a7f0db3
Cr-Commit-Position: refs/heads/master@{#11926}
==========

[commit-bot: I haz the power, 2016-03-09 09:41:02]

Patchset 1 (id:??) landed as
https://crrev.com/16daaa5a407e0b7c6918ee0974d1b00c5a7f0db3
Cr-Commit-Position: refs/heads/master@{#11926}