ash: Restore user selected rotation on startup

ash: Restore user selected rotation on startup

Display preferences saves the user selected rotation. We want to restore
it on startup otherwise the rotation will not be restored after the
first Chrome restart.

Example reproduction steps:
1) Log in
2) Set rotation to 90 degrees
3) Restart chrome (this will be fine since it reads the 90 degree
   rotation, though it will write a rotation of 0 degrees)
4) Restart chrome (this will show with a rotation of 0 degrees)

BUG=498895
Committed: https://crrev.com/a56eca844bbca1cdcb741b820ee9631b49252e00
Cr-Commit-Position: refs/heads/master@{#334152}

[dnicoara, 2015-06-10 22:37:56]

dnicoara@chromium.org changed reviewers:
+ jonross@chromium.org, mukai@chromium.org

[Jun Mukai, 2015-06-10 22:55:54]

mukai@chromium.org changed reviewers:
+ oshima@chromium.org

[Jun Mukai, 2015-06-10 22:55:54]

oshima, could you review this?

[oshima, 2015-06-11 00:03:43]

lgtm but please wait for jonross@'s review.

[dnicoara, 2015-06-11 13:53:09]

The CQ bit was checked by dnicoara@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-06-11 13:53:22]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1177863002/20001

[commit-bot: I haz the power, 2015-06-11 14:24:23]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-11 14:24:24]

Dry run: This issue passed the CQ dry run.

[jonross, 2015-06-12 13:21:46]

On 2015/06/11 14:24:24, commit-bot: I haz the power wrote:
> Dry run: This issue passed the CQ dry run.

LGTM, thanks!

[dnicoara, 2015-06-12 13:28:36]

The CQ bit was checked by dnicoara@chromium.org

[commit-bot: I haz the power, 2015-06-12 13:28:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1177863002/20001

[commit-bot: I haz the power, 2015-06-12 13:32:59]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-12 13:34:02]

Patchset 2 (id:??) landed as
https://crrev.com/a56eca844bbca1cdcb741b820ee9631b49252e00
Cr-Commit-Position: refs/heads/master@{#334152}