Implement support for "keyids" Initialization Data format

Implement support for "keyids" Initialization Data format

As Clear Key now handles this format, add it to the key system
registry.

BUG=442982
TEST=new tests pass

Committed: https://crrev.com/bd57c3e80efc3546e3acf3dcb530d88978523af6
Cr-Commit-Position: refs/heads/master@{#321176}

[jrummell, 2015-03-17 01:26:45]

jrummell@chromium.org changed reviewers:
+ ddorwin@chromium.org, sandersd@chromium.org

[jrummell, 2015-03-17 01:26:45]

PTAL. Have a layout test coming in a subsequent CL.

[sandersd (OOO until July 31), 2015-03-17 22:20:13]

lgtm

[jrummell, 2015-03-18 17:02:10]

The CQ bit was checked by jrummell@chromium.org

[commit-bot: I haz the power, 2015-03-18 17:02:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1014733002/1

[commit-bot: I haz the power, 2015-03-18 18:29:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-18 18:30:12]

Patchset 1 (id:??) landed as
https://crrev.com/bd57c3e80efc3546e3acf3dcb530d88978523af6
Cr-Commit-Position: refs/heads/master@{#321176}