ChromeOS: GetProfileByUser should not be called from Preferences::Init.

ChromeOS: GetProfileByUser should not be called from Preferences::Init.

This fixes crash, because GetProfileByUser is now returning NULL there.

BUG=411216, 410617
TEST=manual

Committed: https://crrev.com/829e2bf7e125704e05701017891d2ffdfc3755fd
Cr-Commit-Position: refs/heads/master@{#293614}

[Alexander Alekseev, 2014-09-05 18:50:17]

alemate@chromium.org changed reviewers:
+ xiyuan@chromium.org

[Alexander Alekseev, 2014-09-05 18:50:17]

Please review.

[xiyuan, 2014-09-05 19:13:58]

lgtm

[Alexander Alekseev, 2014-09-05 19:14:15]

The CQ bit was checked by alemate@chromium.org

[Alexander Alekseev, 2014-09-05 19:14:24]

The CQ bit was unchecked by alemate@chromium.org

[Alexander Alekseev, 2014-09-05 19:14:25]

The CQ bit was checked by alemate@chromium.org

[commit-bot: I haz the power, 2014-09-05 19:14:58]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/alemate@chromium.org/543163002/1

[commit-bot: I haz the power, 2014-09-05 22:03:42]

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

[commit-bot: I haz the power, 2014-09-05 22:03:43]

Try jobs failed on following builders:
  android_dbg_tests_recipe on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_dbg_tes...)

[Alexander Alekseev, 2014-09-06 07:09:29]

The CQ bit was checked by alemate@chromium.org

[commit-bot: I haz the power, 2014-09-06 07:11:29]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/alemate@chromium.org/543163002/1

[commit-bot: I haz the power, 2014-09-06 10:32:33]

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

[commit-bot: I haz the power, 2014-09-06 10:32:34]

Exceeded time limit waiting for builds to trigger.

[Alexander Alekseev, 2014-09-06 13:23:20]

The CQ bit was checked by alemate@chromium.org

[commit-bot: I haz the power, 2014-09-06 13:24:21]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/alemate@chromium.org/543163002/1

[commit-bot: I haz the power, 2014-09-06 13:25:33]

Committed patchset #1 (id:1) as b8c5d8c896933a82ba879e8396cc1c4cdbf5af67

[commit-bot: I haz the power, 2014-09-10 03:42:30]

Patchset 1 (id:??) landed as
https://crrev.com/829e2bf7e125704e05701017891d2ffdfc3755fd
Cr-Commit-Position: refs/heads/master@{#293614}