[Extensions Toolbar Views] Add a ToolbarActionView unittest

[Extensions Toolbar Views] Add a ToolbarActionView unittest

Add unittesting for ToolbarActionView to, at minimum, test the basic UI. Also
remove the dependency of ToolbarActionView on Browser, and create a
TestToolbarActionViewController.

BUG=453841
TBR=sky@chromium.org (gn file change)

Committed: https://crrev.com/bb461c8f803f441364fdbb9f5124045771daa31a
Cr-Commit-Position: refs/heads/master@{#315130}

[Devlin, 2015-01-31 00:35:12]

rdevlin.cronin@chromium.org changed reviewers:
+ finnur@chromium.org

[Finnur, 2015-02-02 12:08:10]

LGTM

[Devlin, 2015-02-06 22:58:53]

The CQ bit was checked by rdevlin.cronin@chromium.org

[commit-bot: I haz the power, 2015-02-06 23:00:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/888043003/40001

[commit-bot: I haz the power, 2015-02-06 23:06:03]

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

[commit-bot: I haz the power, 2015-02-06 23:06:04]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[Devlin, 2015-02-06 23:14:34]

rdevlin.cronin@chromium.org changed reviewers:
+ sky@chromium.org

[Devlin, 2015-02-06 23:14:40]

The CQ bit was checked by rdevlin.cronin@chromium.org

[commit-bot: I haz the power, 2015-02-06 23:15:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/888043003/40001

[commit-bot: I haz the power, 2015-02-06 23:19:58]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-02-06 23:20:36]

Patchset 3 (id:??) landed as
https://crrev.com/bb461c8f803f441364fdbb9f5124045771daa31a
Cr-Commit-Position: refs/heads/master@{#315130}