Add rtc::Optional::reset

Add rtc::Optional::reset

BUG=None

Committed: https://crrev.com/c4fd23cdda1fb6b8f1ac5f3105c864c22c3ce704
Cr-Commit-Position: refs/heads/master@{#14651}

[danilchap, 2016-10-17 12:11:15]

danilchap@webrtc.org changed reviewers:
+ kwiberg@webrtc.org

[danilchap, 2016-10-17 12:11:15]

Does it make sense to implement emplace too?
or there is short-term plan to import chromium implementation of the Optional
that already has both reset and emplace.

[kwiberg-webrtc, 2016-10-17 12:21:38]

lgtm.

And no, there's unfortunately no short-term plan to steal Chromium's Optional;
it shouldn't be hard to do, except it'd be neat to first build sanitizer support
into their Optional so that we don't lose that support when we steal it.

If you feel like implementing more of the standard functionality (with tests)
rather than wait, go ahead. Or if you feel like stealing their Optional without
first equipping it with sanitizer support, go ahead and do that. Of course, if
you feel like going for the full shebang, I'll be happy to help review it...

[danilchap, 2016-10-17 12:47:43]

The CQ bit was checked by danilchap@webrtc.org

[commit-bot: I haz the power, 2016-10-17 12:47:53]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2016-10-17 14:16:57]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-10-17 14:17:04]

Description was changed from

==========
Add rtc::Optional::reset

BUG=None
==========

to

==========
Add rtc::Optional::reset

BUG=None

Committed: https://crrev.com/c4fd23cdda1fb6b8f1ac5f3105c864c22c3ce704
Cr-Commit-Position: refs/heads/master@{#14651}
==========

[commit-bot: I haz the power, 2016-10-17 14:17:05]

Patchset 3 (id:??) landed as
https://crrev.com/c4fd23cdda1fb6b8f1ac5f3105c864c22c3ce704
Cr-Commit-Position: refs/heads/master@{#14651}