Minor cleanup in EasyUnlockClient

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}

[tbarzic, 2014-09-15 19:05:14]

tbarzic@chromium.org changed reviewers:
+ stevenjb@chromium.org

[tbarzic, 2014-09-15 19:35:08]

tbarzic@chromium.org changed reviewers:
+ isherman@chromium.org

[tbarzic, 2014-09-15 19:35:09]

+isherman (in case this collides with some of your refactoring)

[stevenjb, 2014-09-15 20:28:34]

lgtm

[Ilya Sherman, 2014-09-15 21:34:43]

Thanks for the heads-up.  This doesn't conflict with the refactoring that I'm
working on.

[tbarzic, 2014-09-15 22:56:51]

The CQ bit was checked by tbarzic@chromium.org

[commit-bot: I haz the power, 2014-09-15 23:32:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/569813002/20001

[commit-bot: I haz the power, 2014-09-16 01:02:16]

Committed patchset #2 (id:20001) as 5eef5ca6d7a1c0829f86fca731ee9adaabb25535

[commit-bot: I haz the power, 2014-09-16 01:05:39]

Patchset 2 (id:??) landed as
https://crrev.com/35e3a9c7061205db58f57182f5ba5eb87be0f355
Cr-Commit-Position: refs/heads/master@{#294954}

[Ken Rockot(use gerrit already), 2014-09-16 01:46:10]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/577443004/ by rockot@chromium.org.

The reason for reverting is: Looks like some ChromeOS code was missed here; it's
unclear why bots didn't catch this..

[tbarzic, 2014-09-16 21:51:27]

On 2014/09/16 01:46:10, Ken Rockot wrote:
> A revert of this CL (patchset #2 id:20001) has been created in
> https://codereview.chromium.org/577443004/ by mailto:rockot@chromium.org.
> 
> The reason for reverting is: Looks like some ChromeOS code was missed here;
it's
> unclear why bots didn't catch this..

relanding in https://codereview.chromium.org/581463002/