Remove RTCAVFoundationVideoSource

Remove RTCAVFoundationVideoSource

RTCAVFoundationVideoSource has been deprecated and replaced with a
generic RTCVideoSource combined with an RTCVideoCapturer implementation,
e.g. RTCCameraVideoCapturer.

BUG=webrtc:7177

[magjed_webrtc, 2017-07-31 12:52:35]

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

[commit-bot: I haz the power, 2017-07-31 12:52:45]

Dry run: 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, 2017-07-31 13:10:33]

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

[commit-bot: I haz the power, 2017-07-31 13:10:34]

Dry run: This issue passed the CQ dry run.

[magjed_webrtc, 2017-07-31 14:51:58]

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

[commit-bot: I haz the power, 2017-07-31 14:52:03]

Dry run: CQ is trying da patch.

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

[magjed_webrtc, 2017-07-31 14:56:18]

Patchset #2 (id:20001) has been deleted

[magjed_webrtc, 2017-07-31 14:56:26]

Patchset #1 (id:1) has been deleted

[magjed_webrtc, 2017-07-31 15:13:55]

Description was changed from

==========
Remove RTCAVFoundationVideoSource

RTCAVFoundationVideoSource has been deprecated and replaced with a
generic RTCVideoSource combined with an RTCVideoCapturer implementation,
e.g. RTCCameraVideoCapturer.

BUG=webrtc:7177
==========

to

==========
Remove RTCAVFoundationVideoSource

RTCAVFoundationVideoSource has been deprecated and replaced with a
generic RTCVideoSource combined with an RTCVideoCapturer implementation,
e.g. RTCCameraVideoCapturer.

BUG=webrtc:7177
==========

[magjed_webrtc, 2017-07-31 15:13:56]

magjed@webrtc.org changed reviewers:
+ deadbeef@webrtc.org, denicija@webrtc.org

[magjed_webrtc, 2017-07-31 15:14:49]

Please take a look.

Note that I won't land this in a while, because we need to deprecate
RTCAVFoundationVideoSource and make a PSA and give it some time before we remote
it.

[commit-bot: I haz the power, 2017-07-31 15:31:14]

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

[commit-bot: I haz the power, 2017-07-31 15:31:15]

Dry run: This issue passed the CQ dry run.

[Taylor Brandstetter, 2017-08-01 00:27:56]

lgtm. What does the migration path look like? Could someone fork this code and
continue using RTCAVFoundationVideoSource since it inherits from RTCVideoSource,
if they still need it?

[daniela-webrtc, 2017-08-01 08:36:33]

lgtm