Add a handler for enabled/disabling assist.

Add a handler for enabled/disabling assist.

This disables assist if showing an incognito tab or if
in a tab switcher showing icognito tabs.

BUG=497258
Committed: https://crrev.com/a2147a35be3bd7ab2e3ff3a0aaf498d5f190f5b9
Cr-Commit-Position: refs/heads/master@{#340382}

[Ted C, 2015-07-24 18:49:04]

tedchoc@chromium.org changed reviewers:
+ dtrainor@chromium.org, sgurun@google.com

[Ted C, 2015-07-24 18:49:04]

PTAL

[David Trainor- moved to gerrit, 2015-07-24 19:22:17]

lgtm.  Looks like it covers accessibility overview mode too, but I'd just check
it to make sure.

[sgurun-gerrit only, 2015-07-24 19:53:08]

On 2015/07/24 19:22:17, David Trainor wrote:
> lgtm.  Looks like it covers accessibility overview mode too, but I'd just
check
> it to make sure.

lgtm

[Ted C, 2015-07-24 20:33:27]

tested in accessibility and it works there as well.

[Ted C, 2015-07-24 20:34:34]

The CQ bit was checked by tedchoc@chromium.org

[commit-bot: I haz the power, 2015-07-24 20:36:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1255973004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1255973004/1

[commit-bot: I haz the power, 2015-07-24 20:38:57]

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

[commit-bot: I haz the power, 2015-07-24 20:38:58]

Try jobs failed on following builders:
  ios_dbg_simulator_ninja on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_dbg_simulator...)
  ios_rel_device_ninja on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ni...)
  mac_chromium_compile_dbg_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Ted C, 2015-07-24 23:46:41]

The CQ bit was checked by tedchoc@chromium.org

[Ted C, 2015-07-24 23:46:41]

The patchset sent to the CQ was uploaded after l-g-t-m from sgurun@chromium.org,
dtrainor@chromium.org
Link to the patchset: https://codereview.chromium.org/1255973004/#ps20001
(title: "Rebased")

[commit-bot: I haz the power, 2015-07-24 23:46:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1255973004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1255973004/20001

[commit-bot: I haz the power, 2015-07-25 00:25:31]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-25 00:26:35]

Patchset 2 (id:??) landed as
https://crrev.com/a2147a35be3bd7ab2e3ff3a0aaf498d5f190f5b9
Cr-Commit-Position: refs/heads/master@{#340382}