Changed timeout to 6s for reporting android camera freeze.

Changed timeout to 6s for reporting android camera freeze.
Also distinguish between camera failures and failures due to that buffers has not been returned.
Adds unit tests for making sure CameraEventHandler.onError is triggered if frames are not returned.

BUG=b/25514149

Committed: https://crrev.com/3bfef44a4de22c562bdfd787872ef4a13aa1ad60
Cr-Commit-Position: refs/heads/master@{#10555}

[perkj_webrtc, 2015-11-06 10:16:22]

perkj@webrtc.org changed reviewers:
+ glaznev@webrtc.org

[perkj_webrtc, 2015-11-06 10:16:23]

Can you please review?

[AlexG, 2015-11-06 17:47:58]

lgtm

[perkj_webrtc, 2015-11-08 14:04:48]

The CQ bit was checked by perkj@webrtc.org

[commit-bot: I haz the power, 2015-11-08 14:04:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1415013006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1415013006/1

[commit-bot: I haz the power, 2015-11-08 14:58:20]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-08 14:58:29]

Patchset 1 (id:??) landed as
https://crrev.com/3bfef44a4de22c562bdfd787872ef4a13aa1ad60
Cr-Commit-Position: refs/heads/master@{#10555}