[net/proxy] Usage of ThreadTaskRunnerHandle & SingleThreadTaskRunner instead of MLP

Deprecation of MessageLoopProxy usage with ThreadTaskRunnerHandle in net/proxy module.

BUG=391045
Committed: https://crrev.com/55c065b684f16cee1c73e7ef803764f22a4fb281
Cr-Commit-Position: refs/heads/master@{#330039}

[Pranay, 2015-05-12 13:11:28]

pranay.kumar@samsung.com changed reviewers:
+ rdsmith@chromium.org

[Pranay, 2015-05-12 13:11:29]

PTAL

Thanks

[Randy Smith (Not in Mondays), 2015-05-12 14:02:29]

rdsmith@chromium.org changed reviewers:
+ eroman@chromium.org
- rdsmith@chromium.org

[Randy Smith (Not in Mondays), 2015-05-12 14:02:30]

This is probably a fine change, but I've never worked in the proxy code, so I'm
reluctant to approve it.  Eric?

[eroman, 2015-05-14 23:38:11]

lgtm

[Pranay, 2015-05-15 02:42:08]

The CQ bit was checked by pranay.kumar@samsung.com

[commit-bot: I haz the power, 2015-05-15 02:42:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1141573002/1

[Pranay, 2015-05-15 02:42:35]

Hi Eroman,

Thanks for the LGTM

[eroman, 2015-05-15 02:44:29]

No problem!

If the code is good I am happy to sign off on it :)

[commit-bot: I haz the power, 2015-05-15 04:19:08]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-15 04:19:57]

Patchset 1 (id:??) landed as
https://crrev.com/55c065b684f16cee1c73e7ef803764f22a4fb281
Cr-Commit-Position: refs/heads/master@{#330039}