WebmMuxer: add Pause()/Resume() methods and internal time-in-pause

WebmMuxer: add Pause()/Resume() methods and internal time-in-pause

See bug for more details, but basically, since WebmMuxer relies on the
incoming video/audio packet timestamp, pausing the recorder (not any
associated MediaStream{Video,Audio}Track), leaves empty gaps in the
output .webm file.

This CL solves this by measuring the elapsed time(s) between Pause()
and Resume(), accumulating the elapsed time(s), then subtracting that
from the output webm file timestamp.

BUG=593560
TEST= manual:
- head for QA page [1] (with --enable-blink-features=GetUserMedia)
- click on "GetUSerMedia"
- select "Stream To Record" "local"
- click "CreateRecorder" then "Start".
- Leave it recording for a A seconds.
- Click "Pause" and wait a B seconds.
- Click "Resume" and wait C seconds.
- Click "Stop" and "Download".
- Play back the generated file and verify that there is
no substantial freezing in the recorded sequence and that
the length of the output file is estimated in A+C seconds.

[1] https://cdn.rawgit.com/cricdecyan/mediarecorder/master/manualtest/index.html

Committed: https://crrev.com/768a9b746767f4a4b64a199fd68f9985c7da7ba3
Cr-Commit-Position: refs/heads/master@{#383481}

[mcasas, 2016-03-25 01:48:51]

Patchset #1 (id:1) has been deleted

[mcasas, 2016-03-25 01:49:38]

Description was changed from

==========
WebmMuxer: add Pause()/Resume() methods and internal time-in-pause

See bug for more details, but basically, since WebmMuxer relies on the
incoming video/audio packet timestamp, pausing the recorder (not any
associated MediaStream{Video,Audio}Track), leaves empty gaps in the
output .webm file.

This CL solves this by measuring the elapsed time between Pause() and
Resume(), accumulating those elapsed times, the subtracting it from the
output webm file timestamp.

BUG=593560
TEST= manual:
- head for QA page [1] (with --enable-blink-features=GetUserMedia)
- click on "GetUSerMedia"
- select "Stream To Record" "local"
- click "CreateRecorder" then "Start".
- Leave it recording for a A seconds.
- Click "Pause" and wait a B seconds.
- Click "Resume" and wait C seconds.
- Click "Stop" and "Download".
- Play back the generated file and verify that there is
no substantial freezing in the recorded sequence and that
the length of the output file is estimated in A+C seconds.


[1] https://cdn.rawgit.com/cricdecyan/mediarecorder/master/manualtest/index.html
==========

to

==========
WebmMuxer: add Pause()/Resume() methods and internal time-in-pause

See bug for more details, but basically, since WebmMuxer relies on the
incoming video/audio packet timestamp, pausing the recorder (not any
associated MediaStream{Video,Audio}Track), leaves empty gaps in the
output .webm file.

This CL solves this by measuring the elapsed time(s) between Pause() 
and Resume(), accumulating the elapsed time(s), then subtracting that 
from the output webm file timestamp.

BUG=593560
TEST= manual:
- head for QA page [1] (with --enable-blink-features=GetUserMedia)
- click on "GetUSerMedia"
- select "Stream To Record" "local"
- click "CreateRecorder" then "Start".
- Leave it recording for a A seconds.
- Click "Pause" and wait a B seconds.
- Click "Resume" and wait C seconds.
- Click "Stop" and "Download".
- Play back the generated file and verify that there is
no substantial freezing in the recorded sequence and that
the length of the output file is estimated in A+C seconds.


[1] https://cdn.rawgit.com/cricdecyan/mediarecorder/master/manualtest/index.html
==========

[mcasas, 2016-03-25 01:50:28]

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

[mcasas, 2016-03-25 01:50:29]

miu@ small CL, PTAL

[miu, 2016-03-25 21:49:51]

lgtm

[mcasas, 2016-03-28 05:15:42]

The CQ bit was checked by mcasas@chromium.org

[commit-bot: I haz the power, 2016-03-28 05:15:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1830383003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1830383003/20001

[commit-bot: I haz the power, 2016-03-28 06:30:45]

Description was changed from

==========
WebmMuxer: add Pause()/Resume() methods and internal time-in-pause

See bug for more details, but basically, since WebmMuxer relies on the
incoming video/audio packet timestamp, pausing the recorder (not any
associated MediaStream{Video,Audio}Track), leaves empty gaps in the
output .webm file.

This CL solves this by measuring the elapsed time(s) between Pause() 
and Resume(), accumulating the elapsed time(s), then subtracting that 
from the output webm file timestamp.

BUG=593560
TEST= manual:
- head for QA page [1] (with --enable-blink-features=GetUserMedia)
- click on "GetUSerMedia"
- select "Stream To Record" "local"
- click "CreateRecorder" then "Start".
- Leave it recording for a A seconds.
- Click "Pause" and wait a B seconds.
- Click "Resume" and wait C seconds.
- Click "Stop" and "Download".
- Play back the generated file and verify that there is
no substantial freezing in the recorded sequence and that
the length of the output file is estimated in A+C seconds.


[1] https://cdn.rawgit.com/cricdecyan/mediarecorder/master/manualtest/index.html
==========

to

==========
WebmMuxer: add Pause()/Resume() methods and internal time-in-pause

See bug for more details, but basically, since WebmMuxer relies on the
incoming video/audio packet timestamp, pausing the recorder (not any
associated MediaStream{Video,Audio}Track), leaves empty gaps in the
output .webm file.

This CL solves this by measuring the elapsed time(s) between Pause() 
and Resume(), accumulating the elapsed time(s), then subtracting that 
from the output webm file timestamp.

BUG=593560
TEST= manual:
- head for QA page [1] (with --enable-blink-features=GetUserMedia)
- click on "GetUSerMedia"
- select "Stream To Record" "local"
- click "CreateRecorder" then "Start".
- Leave it recording for a A seconds.
- Click "Pause" and wait a B seconds.
- Click "Resume" and wait C seconds.
- Click "Stop" and "Download".
- Play back the generated file and verify that there is
no substantial freezing in the recorded sequence and that
the length of the output file is estimated in A+C seconds.


[1] https://cdn.rawgit.com/cricdecyan/mediarecorder/master/manualtest/index.html
==========

[commit-bot: I haz the power, 2016-03-28 06:30:46]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2016-03-28 06:32:37]

Description was changed from

==========
WebmMuxer: add Pause()/Resume() methods and internal time-in-pause

See bug for more details, but basically, since WebmMuxer relies on the
incoming video/audio packet timestamp, pausing the recorder (not any
associated MediaStream{Video,Audio}Track), leaves empty gaps in the
output .webm file.

This CL solves this by measuring the elapsed time(s) between Pause() 
and Resume(), accumulating the elapsed time(s), then subtracting that 
from the output webm file timestamp.

BUG=593560
TEST= manual:
- head for QA page [1] (with --enable-blink-features=GetUserMedia)
- click on "GetUSerMedia"
- select "Stream To Record" "local"
- click "CreateRecorder" then "Start".
- Leave it recording for a A seconds.
- Click "Pause" and wait a B seconds.
- Click "Resume" and wait C seconds.
- Click "Stop" and "Download".
- Play back the generated file and verify that there is
no substantial freezing in the recorded sequence and that
the length of the output file is estimated in A+C seconds.


[1] https://cdn.rawgit.com/cricdecyan/mediarecorder/master/manualtest/index.html
==========

to

==========
WebmMuxer: add Pause()/Resume() methods and internal time-in-pause

See bug for more details, but basically, since WebmMuxer relies on the
incoming video/audio packet timestamp, pausing the recorder (not any
associated MediaStream{Video,Audio}Track), leaves empty gaps in the
output .webm file.

This CL solves this by measuring the elapsed time(s) between Pause()
and Resume(), accumulating the elapsed time(s), then subtracting that
from the output webm file timestamp.

BUG=593560
TEST= manual:
- head for QA page [1] (with --enable-blink-features=GetUserMedia)
- click on "GetUSerMedia"
- select "Stream To Record" "local"
- click "CreateRecorder" then "Start".
- Leave it recording for a A seconds.
- Click "Pause" and wait a B seconds.
- Click "Resume" and wait C seconds.
- Click "Stop" and "Download".
- Play back the generated file and verify that there is
no substantial freezing in the recorded sequence and that
the length of the output file is estimated in A+C seconds.

[1] https://cdn.rawgit.com/cricdecyan/mediarecorder/master/manualtest/index.html

Committed: https://crrev.com/768a9b746767f4a4b64a199fd68f9985c7da7ba3
Cr-Commit-Position: refs/heads/master@{#383481}
==========

[commit-bot: I haz the power, 2016-03-28 06:32:38]

Patchset 1 (id:??) landed as
https://crrev.com/768a9b746767f4a4b64a199fd68f9985c7da7ba3
Cr-Commit-Position: refs/heads/master@{#383481}