Support simulcast and spatial layers in VideoQualityTest (PERF NOTE)

Adding support for simulcast and spatial layers into VideoQualityTest

This is a re-land of https://codereview.webrtc.org/1353263005/
which was reverted because of perf-regressions. Changes since that CL:

* Change LayerFilteringTransport to send a padding packet instead of
  dropping it for data that should be filtered out. This prevents
  confusion due to changed sequence numbers.

* Changed timing of stats poller thread in VideoAnalyzer. Startup was
  racy wrt initializion of send_stream_.

* Minor formatting issues.

PERF NOTE: This change will affect some performance numbers slightly.
In particular, {encode_frame_rate, encode_time_ms,
encode_usage_percent, media_bitrate_bps} will change due to timing
of the measurements.

BUG=
R=pbos@webrtc.org
TBR=mflodman@webrtc.org

Committed: https://crrev.com/ce4aef16eec96862199e89b6d3ffe059558ac2c0
Cr-Commit-Position: refs/heads/master@{#10483}

[sprang_webrtc, 2015-10-28 09:06:45]

sprang@webrtc.org changed reviewers:
+ pbos@webrtc.org

[pbos-webrtc, 2015-10-28 14:59:57]

rs-lgtm

[sprang_webrtc, 2015-11-02 12:51:16]

Description was changed from

==========
Adding support for simulcast and spatial layers into VideoQualityTest

This is a re-land of https://codereview.webrtc.org/1353263005/
which was reverted because of perf-regressions. Changes since that CL:

* Change LayerFilteringTransport to send a padding packet instead of
  dropping it for data that should be filtered out. This prevents
  confusion due to changed sequence numbers.

* Changed timing of stats poller thread in VideoAnalyzer. Startup was
  racy wrt initializion of send_stream_.

* Minor formatting issues.

BUG=
==========

to

==========
Adding support for simulcast and spatial layers into VideoQualityTest

This is a re-land of https://codereview.webrtc.org/1353263005/
which was reverted because of perf-regressions. Changes since that CL:

* Change LayerFilteringTransport to send a padding packet instead of
  dropping it for data that should be filtered out. This prevents
  confusion due to changed sequence numbers.

* Changed timing of stats poller thread in VideoAnalyzer. Startup was
  racy wrt initializion of send_stream_.

* Minor formatting issues.

BUG=
TBR=mflodman@webrtc.org
==========

[sprang_webrtc, 2015-11-02 12:51:16]

sprang@webrtc.org changed reviewers:
+ mflodman@webrtc.org

[sprang_webrtc, 2015-11-02 13:02:34]

Description was changed from

==========
Adding support for simulcast and spatial layers into VideoQualityTest

This is a re-land of https://codereview.webrtc.org/1353263005/
which was reverted because of perf-regressions. Changes since that CL:

* Change LayerFilteringTransport to send a padding packet instead of
  dropping it for data that should be filtered out. This prevents
  confusion due to changed sequence numbers.

* Changed timing of stats poller thread in VideoAnalyzer. Startup was
  racy wrt initializion of send_stream_.

* Minor formatting issues.

BUG=
TBR=mflodman@webrtc.org
==========

to

==========
Adding support for simulcast and spatial layers into VideoQualityTest

This is a re-land of https://codereview.webrtc.org/1353263005/
which was reverted because of perf-regressions. Changes since that CL:

* Change LayerFilteringTransport to send a padding packet instead of
  dropping it for data that should be filtered out. This prevents
  confusion due to changed sequence numbers.

* Changed timing of stats poller thread in VideoAnalyzer. Startup was
  racy wrt initializion of send_stream_.

* Minor formatting issues.

PERF NOTE: This change will affect some performance numbers slightly.
In particular, {encode_frame_rate, encode_time_ms, 
encode_usage_percent, media_bitrate_bps} will change due to timing
of the measurements. 

BUG=
TBR=mflodman@webrtc.org
==========

[sprang_webrtc, 2015-11-02 14:22:19]

The CQ bit was checked by sprang@webrtc.org

[sprang_webrtc, 2015-11-02 14:22:20]

The patchset sent to the CQ was uploaded after l-g-t-m from pbos@webrtc.org
Link to the patchset: https://codereview.webrtc.org/1412233003/#ps40001 (title:
"Rebase + suppress log spamming")

[commit-bot: I haz the power, 2015-11-02 14:22:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1412233003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1412233003/40001

[pbos-webrtc, 2015-11-02 14:34:30]

Description was changed from

==========
Adding support for simulcast and spatial layers into VideoQualityTest

This is a re-land of https://codereview.webrtc.org/1353263005/
which was reverted because of perf-regressions. Changes since that CL:

* Change LayerFilteringTransport to send a padding packet instead of
  dropping it for data that should be filtered out. This prevents
  confusion due to changed sequence numbers.

* Changed timing of stats poller thread in VideoAnalyzer. Startup was
  racy wrt initializion of send_stream_.

* Minor formatting issues.

PERF NOTE: This change will affect some performance numbers slightly.
In particular, {encode_frame_rate, encode_time_ms, 
encode_usage_percent, media_bitrate_bps} will change due to timing
of the measurements. 

BUG=
TBR=mflodman@webrtc.org
==========

to

==========
Adding support for simulcast and spatial layers into VideoQualityTest

This is a re-land of https://codereview.webrtc.org/1353263005/
which was reverted because of perf-regressions. Changes since that CL:

* Change LayerFilteringTransport to send a padding packet instead of
  dropping it for data that should be filtered out. This prevents
  confusion due to changed sequence numbers.

* Changed timing of stats poller thread in VideoAnalyzer. Startup was
  racy wrt initializion of send_stream_.

* Minor formatting issues.

PERF NOTE: This change will affect some performance numbers slightly.
In particular, {encode_frame_rate, encode_time_ms, 
encode_usage_percent, media_bitrate_bps} will change due to timing
of the measurements. 

BUG=
R=pbos@webrtc.org
TBR=mflodman@webrtc.org
==========

[commit-bot: I haz the power, 2015-11-02 15:23:24]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-11-02 15:23:34]

Patchset 3 (id:??) landed as
https://crrev.com/ce4aef16eec96862199e89b6d3ffe059558ac2c0
Cr-Commit-Position: refs/heads/master@{#10483}