Remove webrtc::Config from ViEChannelGroup.

Remove webrtc::Config from ViEChannelGroup.

Also removing webrtc/experiments.h which is no longer used.

BUG=webrtc:1695
R=stefan@webrtc.org
TBR=mflodman@webrtc.org

Committed: https://crrev.com/ef35f069e739feaae16fdfcc815d7af5cb05e9ae
Cr-Commit-Position: refs/heads/master@{#9642}

[pbos-webrtc, 2015-07-23 14:57:17]

PTAL

[pbos-webrtc, 2015-07-23 14:57:23]

The CQ bit was checked by pbos@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-23 14:57:34]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1250513006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1250513006/1

[commit-bot: I haz the power, 2015-07-23 14:58:58]

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

[commit-bot: I haz the power, 2015-07-23 14:58:59]

Dry run: Try jobs failed on following builders:
  win on tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/win/builds/8837)

[pbos-webrtc, 2015-07-24 08:20:32]

remove experiment.h from build files

[pbos-webrtc, 2015-07-24 08:20:38]

The CQ bit was checked by pbos@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-24 08:20:47]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1250513006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1250513006/20001

[commit-bot: I haz the power, 2015-07-24 09:52:15]

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

[commit-bot: I haz the power, 2015-07-24 09:52:15]

Dry run: This issue passed the CQ dry run.

[stefan-webrtc, 2015-07-27 14:02:05]

stefan@webrtc.org changed reviewers:
+ stefan@webrtc.org

[stefan-webrtc, 2015-07-27 14:02:06]

lgtm

[pbos-webrtc, 2015-07-27 14:10:59]

The CQ bit was checked by pbos@webrtc.org

[commit-bot: I haz the power, 2015-07-27 14:11:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1250513006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1250513006/20001

[commit-bot: I haz the power, 2015-07-27 15:37:10]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-27 15:37:26]

Patchset 2 (id:??) landed as
https://crrev.com/ef35f069e739feaae16fdfcc815d7af5cb05e9ae
Cr-Commit-Position: refs/heads/master@{#9642}