Remove pure-virtual MediaStreamProvider::Unregister method and make overrides non-virtual.

Remove pure-virtual MediaStreamProvider::Unregister method and make overrides non-virtual.

The method is never called via virtual method dispatch, only directly on subclasses.

Committed: https://crrev.com/0f0d0b39f878fdf6798235b2a4f7e01140d53083
Cr-Commit-Position: refs/heads/master@{#305222}

[Bernhard Bauer, 2014-11-07 12:13:33]

bauerb@chromium.org changed reviewers:
+ xians@chromium.org

[Bernhard Bauer, 2014-11-07 12:13:33]

Please review.

[Bernhard Bauer, 2014-11-21 13:57:20]

bauerb@chromium.org changed reviewers:
- xians@chromium.org

[Bernhard Bauer, 2014-11-21 13:58:05]

bauerb@chromium.org changed reviewers:
+ tommi@chromium.org

[Bernhard Bauer, 2014-11-21 13:58:06]

Tommi, can you take a look?

[tommi (sloooow) - chröme, 2014-11-21 15:28:06]

The CQ bit was checked by tommi@chromium.org

[tommi (sloooow) - chröme, 2014-11-21 15:28:07]

lgtm

[commit-bot: I haz the power, 2014-11-21 15:28:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/701103002/1

[commit-bot: I haz the power, 2014-11-21 16:19:57]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-11-21 16:20:47]

Patchset 1 (id:??) landed as
https://crrev.com/0f0d0b39f878fdf6798235b2a4f7e01140d53083
Cr-Commit-Position: refs/heads/master@{#305222}