Add API tests for the chrome.hid API.

Add API tests for the chrome.hid API.

These test validate that the implementation of the chrome.hid API is using
the API provided by //device/hid correctly. It does not talk to real devices
or validate platform-specific functionality.

BUG=

Committed: https://crrev.com/e48477cd0a73dce8d17a2a6290434602252d6ba6
Cr-Commit-Position: refs/heads/master@{#302117}

[Reilly Grant (use Gerrit), 2014-10-29 23:02:45]

Patchset #1 (id:1) has been deleted

[Reilly Grant (use Gerrit), 2014-10-29 23:08:24]

rockot@, please take a look at these awesome tests!

[Reilly Grant (use Gerrit), 2014-10-30 14:16:53]

reillyg@chromium.org changed reviewers:
+ rockot@chromium.org

[Reilly Grant (use Gerrit), 2014-10-30 14:17:15]

Now that I've actually added you to the reviewers list: rockot@, please take a
look at these awesome tests!

[Ken Rockot(use gerrit already), 2014-10-30 17:20:50]

I agree that these are awesome tests! lgtm

[Reilly Grant (use Gerrit), 2014-10-30 17:41:40]

The CQ bit was checked by reillyg@chromium.org

[commit-bot: I haz the power, 2014-10-30 17:42:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/690473002/20001

[commit-bot: I haz the power, 2014-10-30 18:42:28]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2014-10-30 18:43:02]

Patchset 1 (id:??) landed as
https://crrev.com/e48477cd0a73dce8d17a2a6290434602252d6ba6
Cr-Commit-Position: refs/heads/master@{#302117}