Revert of Minor cleanup in EasyUnlockClient

Revert of Minor cleanup in EasyUnlockClient (patchset #2 id:20001 of https://codereview.chromium.org/569813002/)

Reason for revert:
Looks like some ChromeOS code was missed here; it's unclear why bots didn't catch this.

Original issue's description:
> Minor cleanup in EasyUnlockClient
>
> * arg names in GenerateEcP256KeyPairCallback typedef were reversed
> * Make CreateSecureMEssage and UnwrapSecureMessage take structs (instead
> of having long list of arguments)
>
> BUG=None
> TEST=existing unittests
>
> Committed: https://crrev.com/35e3a9c7061205db58f57182f5ba5eb87be0f355
> Cr-Commit-Position: refs/heads/master@{#294954}

TBR=stevenjb@chromium.org,isherman@chromium.org,tbarzic@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=None

Committed: https://crrev.com/b90decf7bb94f829c52601e284566e881f3774bb
Cr-Commit-Position: refs/heads/master@{#294968}

[Ken Rockot(use gerrit already), 2014-09-16 01:46:11]

Created Revert of Minor cleanup in EasyUnlockClient

[commit-bot: I haz the power, 2014-09-16 01:48:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/577443004/1

[commit-bot: I haz the power, 2014-09-16 01:52:08]

Committed patchset #1 (id:1) as a47635efe35bdf05438974eb6cc66f8a102ad7c1

[commit-bot: I haz the power, 2014-09-16 01:53:59]

Patchset 1 (id:??) landed as
https://crrev.com/b90decf7bb94f829c52601e284566e881f3774bb
Cr-Commit-Position: refs/heads/master@{#294968}