Switch HidDeviceId from IORegistry path to IORegistry entry ID.

Switch HidDeviceId from IORegistry path to IORegistry entry ID.

As of OS X Yosemite the IORegistry paths for Bluetooth HID devices
are no longer unique. This change switches to using the entry IDs
instead, which appear to remain unique.

BUG=452172
Committed: https://crrev.com/fab70f55e19d3090af7d6d51425abed3c8b3e039
Cr-Commit-Position: refs/heads/master@{#321892}

[Reilly Grant (use Gerrit), 2015-03-23 22:14:57]

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

[Reilly Grant (use Gerrit), 2015-03-23 22:15:17]

Please look at this one too.

[Ken Rockot(use gerrit already), 2015-03-23 22:38:45]

lgtm

[Reilly Grant (use Gerrit), 2015-03-23 22:41:24]

The CQ bit was checked by reillyg@chromium.org

[commit-bot: I haz the power, 2015-03-23 22:42:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1025553004/1

[commit-bot: I haz the power, 2015-03-23 23:21:25]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-23 23:22:00]

Patchset 1 (id:??) landed as
https://crrev.com/fab70f55e19d3090af7d6d51425abed3c8b3e039
Cr-Commit-Position: refs/heads/master@{#321892}