Fix two invalid DCHECKs related to audio BWE.

Fix two invalid DCHECKs related to audio BWE.

These are invalid since:
- An allocated bitrate of 0 means that the stream should be disabled. Changing the behavior to send audio at min bitrate even though the allocator asks for the stream to be disabled.
- It should be OK to set a min bitrate equal to the start bitrate.

BUG=webrtc:5079
Review-Url: https://codereview.webrtc.org/2806163003
Cr-Commit-Position: refs/heads/master@{#17613}
Committed: https://chromium.googlesource.com/external/webrtc/+/fca900aa3767bc6800e2119e4135965895b54e2c

[stefan-webrtc, 2017-04-10 09:46:13]

Description was changed from

==========
Fix two invalid DCHECKs related to audio BWE.

These are invalid since:
- An allocated bitrate of 0 means that the stream should be disabled. Changing
the behavior to send audio at min bitrate even though the allocator asks for the
stream to be disabled.
- It should be OK to set a min bitrate equal to the start bitrate.

BUG=None
==========

to

==========
Fix two invalid DCHECKs related to audio BWE.

These are invalid since:
- An allocated bitrate of 0 means that the stream should be disabled. Changing
the behavior to send audio at min bitrate even though the allocator asks for the
stream to be disabled.
- It should be OK to set a min bitrate equal to the start bitrate.

BUG=webrtc:5079
==========

[stefan-webrtc, 2017-04-10 09:46:19]

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

[stefan-webrtc, 2017-04-10 09:47:46]

Add comment.

[stefan-webrtc, 2017-04-10 09:48:02]

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

[commit-bot: I haz the power, 2017-04-10 09:48:11]

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

[minyue-webrtc, 2017-04-10 09:52:05]

lgtm

[commit-bot: I haz the power, 2017-04-10 10:11:39]

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

[commit-bot: I haz the power, 2017-04-10 10:11:40]

Dry run: This issue passed the CQ dry run.

[stefan-webrtc, 2017-04-10 10:50:07]

The CQ bit was checked by stefan@webrtc.org

[commit-bot: I haz the power, 2017-04-10 10:50:23]

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, 2017-04-10 10:53:00]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1491821407297730,
"parent_rev": "49cad02cf38dc54f8ba0bdab28c3dbd21f1d4e81", "commit_rev":
"fca900aa3767bc6800e2119e4135965895b54e2c"}

[commit-bot: I haz the power, 2017-04-10 10:53:03]

Description was changed from

==========
Fix two invalid DCHECKs related to audio BWE.

These are invalid since:
- An allocated bitrate of 0 means that the stream should be disabled. Changing
the behavior to send audio at min bitrate even though the allocator asks for the
stream to be disabled.
- It should be OK to set a min bitrate equal to the start bitrate.

BUG=webrtc:5079
==========

to

==========
Fix two invalid DCHECKs related to audio BWE.

These are invalid since:
- An allocated bitrate of 0 means that the stream should be disabled. Changing
the behavior to send audio at min bitrate even though the allocator asks for the
stream to be disabled.
- It should be OK to set a min bitrate equal to the start bitrate.

BUG=webrtc:5079

Review-Url: https://codereview.webrtc.org/2806163003
Cr-Commit-Position: refs/heads/master@{#17613}
Committed:
https://chromium.googlesource.com/external/webrtc/+/fca900aa3767bc6800e2119e4...
==========

[commit-bot: I haz the power, 2017-04-10 10:53:04]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/external/webrtc/+/fca900aa3767bc6800e2119e4...