[Video] Fix keyframe distance average calculations.

[Video] Fix keyframe distance average calculations.

Found a few problems with the way the keyframe distance is calculated and
passed from the decoder to WMPI:
1. as soon as the video decoder is stopped we reset the average - meaning we
will stop considering optimizing playback for the video
2. we have to wait for more than 4 keyframes to start optimizing video
playback, this can take seconds
3. audio decoder resets the average to 0 in pipeline's shared state

BUG=None
TEST=Manual

Review-Url: https://codereview.chromium.org/2643103002
Cr-Commit-Position: refs/heads/master@{#444955}
Committed: https://chromium.googlesource.com/chromium/src/+/8127a839bf18e618aaf7a8cad95440c6cd3f9f76

[whywhat, 2017-01-19 21:02:35]

avayvod@chromium.org changed reviewers:
+ dalecurtis@chromium.org

[whywhat, 2017-01-19 21:02:35]

PTaL

[DaleCurtis, 2017-01-19 21:10:23]

lgtm

[whywhat, 2017-01-19 22:20:23]

The CQ bit was checked by avayvod@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-01-19 22:21:02]

Dry run: 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, 2017-01-20 01:13:48]

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

[commit-bot: I haz the power, 2017-01-20 01:13:49]

Dry run: This issue passed the CQ dry run.

[whywhat, 2017-01-20 02:09:10]

The CQ bit was checked by avayvod@chromium.org

[commit-bot: I haz the power, 2017-01-20 02:09:53]

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, 2017-01-20 02:15:40]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1484878150268770, "parent_rev":
"ffa5d9bdfbbcf4242213f8c48e5af56ae543b5de", "commit_rev":
"8127a839bf18e618aaf7a8cad95440c6cd3f9f76"}

[commit-bot: I haz the power, 2017-01-20 02:16:09]

Description was changed from

==========
[Video] Fix keyframe distance average calculations.

Found a few problems with the way the keyframe distance is calculated and
passed from the decoder to WMPI:
1. as soon as the video decoder is stopped we reset the average - meaning we
will stop considering optimizing playback for the video
2. we have to wait for more than 4 keyframes to start optimizing video
playback, this can take seconds
3. audio decoder resets the average to 0 in pipeline's shared state

BUG=None
TEST=Manual
==========

to

==========
[Video] Fix keyframe distance average calculations.

Found a few problems with the way the keyframe distance is calculated and
passed from the decoder to WMPI:
1. as soon as the video decoder is stopped we reset the average - meaning we
will stop considering optimizing playback for the video
2. we have to wait for more than 4 keyframes to start optimizing video
playback, this can take seconds
3. audio decoder resets the average to 0 in pipeline's shared state

BUG=None
TEST=Manual

Review-Url: https://codereview.chromium.org/2643103002
Cr-Commit-Position: refs/heads/master@{#444955}
Committed:
https://chromium.googlesource.com/chromium/src/+/8127a839bf18e618aaf7a8cad954...
==========

[commit-bot: I haz the power, 2017-01-20 02:16:12]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/8127a839bf18e618aaf7a8cad954...