Refactor webrtc/modules/audio_conference_mixer for GN check

Refactor webrtc/modules/audio_conference_mixer for GN check

This moves some GN check configurations out of .gn to individual
targets.

The now checked target is:
"//webrtc/modules/audio_conference_mixer/*"

BUG=webrtc:6828
NOTRY=True

Review-Url: https://codereview.webrtc.org/2593003002
Cr-Commit-Position: refs/heads/master@{#15759}
Committed: https://chromium.googlesource.com/external/webrtc/+/000d16396e748c7593ac41b24a876a6c20f0d277

[mbonadei, 2016-12-21 14:54:41]

mbonadei@webrtc.org changed reviewers:
+ kjellander@webrtc.org

[kjellander_webrtc, 2016-12-22 08:20:57]

lgtm, but since we had a very hard-to-spot breakage in another CL, let's run
Chromium trybots for all these patches to prevent similar breakages.
See https://webrtc.org/contributing/#tryjobs-on-chromium-trybots for a useful
command line to run.

[mbonadei, 2016-12-22 14:54:15]

The CQ bit was checked by mbonadei@webrtc.org

[mbonadei, 2016-12-22 14:54:15]

The patchset sent to the CQ was uploaded after l-g-t-m from
kjellander@webrtc.org
Link to the patchset: https://codereview.webrtc.org/2593003002/#ps60001 (title:
"Revert "Removing .gn changes to run chromium trybots"")

[commit-bot: I haz the power, 2016-12-22 14:54:26]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2016-12-22 14:56:22]

CQ is committing da patch.

Bot data: {"patchset_id": 60001, "attempt_start_ts": 1482418455485770,
"parent_rev": "fb78c3e6fcb2c0499034f76d67894fe25b3f74d9", "commit_rev":
"000d16396e748c7593ac41b24a876a6c20f0d277"}

[commit-bot: I haz the power, 2016-12-22 14:56:24]

Description was changed from

==========
Refactor webrtc/modules/audio_conference_mixer for GN check

This moves some GN check configurations out of .gn to individual
targets.

The now checked target is:
"//webrtc/modules/audio_conference_mixer/*"

BUG=webrtc:6828
NOTRY=True
==========

to

==========
Refactor webrtc/modules/audio_conference_mixer for GN check

This moves some GN check configurations out of .gn to individual
targets.

The now checked target is:
"//webrtc/modules/audio_conference_mixer/*"

BUG=webrtc:6828
NOTRY=True

Review-Url: https://codereview.webrtc.org/2593003002
Cr-Commit-Position: refs/heads/master@{#15759}
Committed:
https://chromium.googlesource.com/external/webrtc/+/000d16396e748c7593ac41b24...
==========

[commit-bot: I haz the power, 2016-12-22 14:56:25]

Committed patchset #4 (id:60001) as
https://chromium.googlesource.com/external/webrtc/+/000d16396e748c7593ac41b24...