MediaSession should use ContextClient instead of ContextLifecycleObserver

MediaSession should use ContextClient instead of ContextLifecycleObserver

ContextClient is more lightweight than ContextLifecycleObserver.
We prefer ContextClient.

BUG=610176
Committed: https://crrev.com/71f33f82d2993c9aebb11b66c0389d7646c2817c
Cr-Commit-Position: refs/heads/master@{#440708}

[haraken, 2016-12-26 06:15:03]

haraken@chromium.org changed reviewers:
+ sigbjornf@opera.com

[haraken, 2016-12-26 06:15:04]

PTAL

[sof, 2016-12-26 06:57:32]

lgtm

[haraken, 2016-12-26 07:12:27]

The CQ bit was checked by haraken@chromium.org

[commit-bot: I haz the power, 2016-12-26 07:12:40]

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, 2016-12-26 10:06:01]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1482736347879050, "parent_rev":
"d8af8616022076b6b9d2977b2f8063c237f955c6", "commit_rev":
"11da5a59464365723a504b92bf9b5f826180629c"}

[commit-bot: I haz the power, 2016-12-26 10:06:28]

Description was changed from

==========
MediaSession should use ContextClient instead of ContextLifecycleObserver

ContextClient is more lightweight than ContextLifecycleObserver.
We prefer ContextClient.

BUG=610176
==========

to

==========
MediaSession should use ContextClient instead of ContextLifecycleObserver

ContextClient is more lightweight than ContextLifecycleObserver.
We prefer ContextClient.

BUG=610176

Review-Url: https://codereview.chromium.org/2602663002
==========

[commit-bot: I haz the power, 2016-12-26 10:06:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-26 10:09:07]

Description was changed from

==========
MediaSession should use ContextClient instead of ContextLifecycleObserver

ContextClient is more lightweight than ContextLifecycleObserver.
We prefer ContextClient.

BUG=610176

Review-Url: https://codereview.chromium.org/2602663002
==========

to

==========
MediaSession should use ContextClient instead of ContextLifecycleObserver

ContextClient is more lightweight than ContextLifecycleObserver.
We prefer ContextClient.

BUG=610176

Committed: https://crrev.com/71f33f82d2993c9aebb11b66c0389d7646c2817c
Cr-Commit-Position: refs/heads/master@{#440708}
==========

[commit-bot: I haz the power, 2016-12-26 10:09:08]

Patchset 1 (id:??) landed as
https://crrev.com/71f33f82d2993c9aebb11b66c0389d7646c2817c
Cr-Commit-Position: refs/heads/master@{#440708}