Revert of RTCRtpReceiver.getContributingSources() added.

Revert of RTCRtpReceiver.getContributingSources() added. (patchset #8 id:160001 of https://codereview.chromium.org/2803693002/ )

Reason for revert:
The dependent CL was reverted due to suspected of:
https://bugs.chromium.org/p/webrtc/issues/detail?id=7465

Original issue's description:
> RTCRtpReceiver.getContributingSources() added.
> 
> Adds RTCRtpReceiver.getContributingSources(),
> https://w3c.github.io/webrtc-pc/#dom-rtcrtpreceiver-getcontributingsources,
> and RTCRtpContributingSource,
> https://w3c.github.io/webrtc-pc/#dom-rtcrtpcontributingsource,
> behind flag "RuntimeEnabled=RTCRtpReceiver".
> 
> Contributing sources come in two flavors, SSRCs and CSRCs. This
> interface represents both. For now we ignore SSRCs and only return
> CSRCs. It was recently decided that SSRCs would be returned in a
> separate method to distinguish between the two cases.
> 
> A LayoutTest is used to thoroughly test all blink functionality with
> regards to CSRCs and the caching of contributing sources. This uses
> mocking to update contributing sources in a predictable way.
> 
> The browsertest verifies that no contributing sources are used in a
> normal peerconnection call. The multiple CSRCs case is currently not
> possible to test in a browsertest so we rely on the LayoutTest (and
> webrtc layer testing of contributing sources).
> 
> BUG=703122
> 
> Review-Url: https://codereview.chromium.org/2803693002
> Cr-Commit-Position: refs/heads/master@{#463199}
> Committed: https://chromium.googlesource.com/chromium/src/+/7a16f508ad712bc38ff72e979dd5155a4015c320

TBR=jochen@chromium.org,deadbeef@chromium.org,foolip@chromium.org,guidou@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=703122
Review-Url: https://codereview.chromium.org/2813443003
Cr-Commit-Position: refs/heads/master@{#463226}
Committed: https://chromium.googlesource.com/chromium/src/+/5209c4a740829998e6f5d78f0771d1fac8d20689

[hbos_chromium, 2017-04-10 12:01:52]

The CQ bit was checked by hbos@chromium.org

[hbos_chromium, 2017-04-10 12:01:53]

Created Revert of RTCRtpReceiver.getContributingSources() added.

[commit-bot: I haz the power, 2017-04-10 12:02:08]

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

[commit-bot: I haz the power, 2017-04-10 12:03:12]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1491825712838370, "parent_rev":
"48fd59f0ef21b6daffc42147ac15bff3aefd4e67", "commit_rev":
"5209c4a740829998e6f5d78f0771d1fac8d20689"}

[commit-bot: I haz the power, 2017-04-10 12:04:04]

Description was changed from

==========
Revert of RTCRtpReceiver.getContributingSources() added. (patchset #8 id:160001
of https://codereview.chromium.org/2803693002/ )

Reason for revert:
The dependent CL was reverted due to suspected of:
https://bugs.chromium.org/p/webrtc/issues/detail?id=7465

Original issue's description:
> RTCRtpReceiver.getContributingSources() added.
> 
> Adds RTCRtpReceiver.getContributingSources(),
> https://w3c.github.io/webrtc-pc/#dom-rtcrtpreceiver-getcontributingsources,
> and RTCRtpContributingSource,
> https://w3c.github.io/webrtc-pc/#dom-rtcrtpcontributingsource,
> behind flag "RuntimeEnabled=RTCRtpReceiver".
> 
> Contributing sources come in two flavors, SSRCs and CSRCs. This
> interface represents both. For now we ignore SSRCs and only return
> CSRCs. It was recently decided that SSRCs would be returned in a
> separate method to distinguish between the two cases.
> 
> A LayoutTest is used to thoroughly test all blink functionality with
> regards to CSRCs and the caching of contributing sources. This uses
> mocking to update contributing sources in a predictable way.
> 
> The browsertest verifies that no contributing sources are used in a
> normal peerconnection call. The multiple CSRCs case is currently not
> possible to test in a browsertest so we rely on the LayoutTest (and
> webrtc layer testing of contributing sources).
> 
> BUG=703122
> 
> Review-Url: https://codereview.chromium.org/2803693002
> Cr-Commit-Position: refs/heads/master@{#463199}
> Committed:
https://chromium.googlesource.com/chromium/src/+/7a16f508ad712bc38ff72e979dd5...

TBR=jochen@chromium.org,deadbeef@chromium.org,foolip@chromium.org,guidou@chro...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=703122
==========

to

==========
Revert of RTCRtpReceiver.getContributingSources() added. (patchset #8 id:160001
of https://codereview.chromium.org/2803693002/ )

Reason for revert:
The dependent CL was reverted due to suspected of:
https://bugs.chromium.org/p/webrtc/issues/detail?id=7465

Original issue's description:
> RTCRtpReceiver.getContributingSources() added.
> 
> Adds RTCRtpReceiver.getContributingSources(),
> https://w3c.github.io/webrtc-pc/#dom-rtcrtpreceiver-getcontributingsources,
> and RTCRtpContributingSource,
> https://w3c.github.io/webrtc-pc/#dom-rtcrtpcontributingsource,
> behind flag "RuntimeEnabled=RTCRtpReceiver".
> 
> Contributing sources come in two flavors, SSRCs and CSRCs. This
> interface represents both. For now we ignore SSRCs and only return
> CSRCs. It was recently decided that SSRCs would be returned in a
> separate method to distinguish between the two cases.
> 
> A LayoutTest is used to thoroughly test all blink functionality with
> regards to CSRCs and the caching of contributing sources. This uses
> mocking to update contributing sources in a predictable way.
> 
> The browsertest verifies that no contributing sources are used in a
> normal peerconnection call. The multiple CSRCs case is currently not
> possible to test in a browsertest so we rely on the LayoutTest (and
> webrtc layer testing of contributing sources).
> 
> BUG=703122
> 
> Review-Url: https://codereview.chromium.org/2803693002
> Cr-Commit-Position: refs/heads/master@{#463199}
> Committed:
https://chromium.googlesource.com/chromium/src/+/7a16f508ad712bc38ff72e979dd5...

TBR=jochen@chromium.org,deadbeef@chromium.org,foolip@chromium.org,guidou@chro...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=703122

Review-Url: https://codereview.chromium.org/2813443003
Cr-Commit-Position: refs/heads/master@{#463226}
Committed:
https://chromium.googlesource.com/chromium/src/+/5209c4a740829998e6f5d78f0771...
==========

[commit-bot: I haz the power, 2017-04-10 12:04:06]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/5209c4a740829998e6f5d78f0771...

[hbos_chromium, 2017-04-10 14:42:19]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2808113002/ by hbos@chromium.org.

The reason for reverting is: Reland. The dependent CL relanded, it was not the
culprit of https://bugs.chromium.org/p/webrtc/issues/detail?id=7465..