Refactor MediaStreamTrack video onmute event.

Refactor MediaStreamTrack video onmute event.

This changes monitoring of video frames delivered to MediaStreamVideoSource to be started when the source is started and stopped when the source is stopped rather than depend on
that the source object is destroyed since destruction is dependent on when blink runs garbage collection.

It removes the unused MediaStreamVideoTrack::SetMuted and GetMuted.

It reduces the need for a thread hop between the io-thread and the render thread for each monitor intervall by only trigger the monitoring callback on if a change has occured.

It reduces the test time of media_stream_video_source_unittest.cc from more than 7s to around 200ms.

BUG=404106
Committed: https://crrev.com/530c4af7cd8af97421b7aaa215ee893c1f6d6e14
Cr-Commit-Position: refs/heads/master@{#292853}

[perkj_chrome, 2014-08-27 10:00:53]

perkj@chromium.org changed reviewers:
+ mcasas@chromium.org

[perkj_chrome, 2014-08-27 10:00:54]

Hej
Can you please review?

[perkj_chrome, 2014-08-27 10:00:55]

Hej
Can you please review?

[mcasas, 2014-08-27 12:52:39]

Big cleanup!

Make sure it works and otherwise LGTM.

In my defense, I thought that MSVS should ping MSVTrack which
will send the muted state upwards towards WebKit/Blink, but
it so happens that is easier to go via WebKit/Blink 
WebMSVSource and not WebMSVTrack, so removing the
MSVTrack muted state handling is both correct and a good 
cleanup.

https://codereview.chromium.org/509873002/diff/20001/content/renderer/media/m...
File content/renderer/media/media_stream_video_source_unittest.cc (right):

https://codereview.chromium.org/509873002/diff/20001/content/renderer/media/m...
content/renderer/media/media_stream_video_source_unittest.cc:201: void
SetSourceSupporedFormats(const media::VideoCaptureFormats& formats) {
s/Suppored/Supported/

https://codereview.chromium.org/509873002/diff/20001/content/renderer/media/m...
content/renderer/media/media_stream_video_source_unittest.cc:204: 
Remove extra empty line.

[perkj_chrome, 2014-09-01 07:30:51]

The CQ bit was checked by perkj@chromium.org

[commit-bot: I haz the power, 2014-09-01 07:31:50]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/perkj@chromium.org/509873002/60001

[commit-bot: I haz the power, 2014-09-01 08:33:06]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/linux_gpu/builds/...)

[commit-bot: I haz the power, 2014-09-01 08:58:40]

Committed patchset #4 (id:60001) as 9544ba9cc78bb9dc26b2ee37485ee17db6a49a32

[commit-bot: I haz the power, 2014-09-10 03:16:13]

Patchset 4 (id:??) landed as
https://crrev.com/530c4af7cd8af97421b7aaa215ee893c1f6d6e14
Cr-Commit-Position: refs/heads/master@{#292853}