[Telemetry] Enable background networking for tab_switching measurements

[Telemetry] Enable background networking for tab_switching measurements

Enable background networking for tab_switching measurements so we get some visibility into power impact.

BUG=None

Committed: https://crrev.com/074f66d56a16304d341c85d0a9a5f02bea96f221
Cr-Commit-Position: refs/heads/master@{#293379}

[jeremy, 2014-09-04 11:05:08]

jeremy@chromium.org changed reviewers:
+ tonyg@chromium.org

[tonyg, 2014-09-04 17:25:09]

The CQ bit was checked by tonyg@chromium.org

[tonyg, 2014-09-04 17:25:09]

lgtm

[commit-bot: I haz the power, 2014-09-04 17:27:22]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jeremy@chromium.org/538963003/20001

[commit-bot: I haz the power, 2014-09-04 21:42:52]

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

[commit-bot: I haz the power, 2014-09-04 21:42:53]

Try jobs failed on following builders:
  mac_chromium_rel_swarming on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)
  win_chromium_rel_swarming on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[tonyg, 2014-09-04 23:04:07]

The CQ bit was checked by tonyg@chromium.org

[commit-bot: I haz the power, 2014-09-04 23:05:58]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jeremy@chromium.org/538963003/20001

[commit-bot: I haz the power, 2014-09-05 00:21:04]

Committed patchset #2 (id:20001) as 60af4009ec0779a3ed448ee8ed9e5062ccbe13d8

[commit-bot: I haz the power, 2014-09-10 03:34:13]

Patchset 2 (id:??) landed as
https://crrev.com/074f66d56a16304d341c85d0a9a5f02bea96f221
Cr-Commit-Position: refs/heads/master@{#293379}