base: remove AsyncSocketIoHandler

base: remove AsyncSocketIoHandler

This code was added a couple of years ago in this CL:

  https://chromiumcodereview.appspot.com/23137015

but was never actually used.

TEST=base_unittests
BUG=

Committed: https://crrev.com/0b62ba881585585804dda84371d5773312ae89c5
Cr-Commit-Position: refs/heads/master@{#350199}

[Elly Fong-Jones, 2015-09-22 16:37:32]

ellyjones@chromium.org changed reviewers:
+ danakj@chromium.org

[Elly Fong-Jones, 2015-09-22 16:37:38]

danakj: PTAL?

[Nico, 2015-09-22 17:11:46]

thakis@chromium.org changed reviewers:
+ thakis@chromium.org

[Nico, 2015-09-22 17:11:46]

lgtm

[Elly Fong-Jones, 2015-09-22 17:13:07]

The CQ bit was checked by ellyjones@chromium.org

[commit-bot: I haz the power, 2015-09-22 17:13:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1349093005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1349093005/1

[commit-bot: I haz the power, 2015-09-22 18:31:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-22 18:44:29]

Patchset 1 (id:??) landed as
https://crrev.com/0b62ba881585585804dda84371d5773312ae89c5
Cr-Commit-Position: refs/heads/master@{#350199}