Implement of privet/v3/auth after pairing.

Implement of privet/v3/auth after pairing.

After successfull pairing session will call auth API to get access token.

BUG=449864
Committed: https://crrev.com/612b593d1f64d82c27b602a73fa2e3dd1c6355e7
Cr-Commit-Position: refs/heads/master@{#313901}

[Vitaly Buka (NO REVIEWS), 2015-01-28 23:56:34]

vitalybuka@chromium.org changed reviewers:
+ alekseys@chromium.org, mednik@chromium.org, zentaro@chromium.org

[Aleksey Shlyapnikov, 2015-01-29 01:04:07]

lgtm

[Aleksey Shlyapnikov, 2015-01-29 01:04:08]

lgtm

[Vitaly Buka (NO REVIEWS), 2015-01-30 09:51:37]

Patchset #3 (id:40001) has been deleted

[Vitaly Buka (NO REVIEWS), 2015-01-30 10:10:45]

The CQ bit was checked by vitalybuka@chromium.org

[commit-bot: I haz the power, 2015-01-30 10:11:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/880373004/60001

[commit-bot: I haz the power, 2015-01-30 10:21:57]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-30 10:21:58]

Try jobs failed on following builders:
  linux_chromium_gn_chromeos_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Vitaly Buka (NO REVIEWS), 2015-01-30 10:25:55]

The CQ bit was checked by vitalybuka@chromium.org

[commit-bot: I haz the power, 2015-01-30 10:26:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/880373004/80001

[commit-bot: I haz the power, 2015-01-30 12:12:26]

Committed patchset #4 (id:80001)

[commit-bot: I haz the power, 2015-01-30 12:13:40]

Patchset 4 (id:??) landed as
https://crrev.com/612b593d1f64d82c27b602a73fa2e3dd1c6355e7
Cr-Commit-Position: refs/heads/master@{#313901}