Fixed Chrome OS password changing dialog.

Fixed Chrome OS password changing dialog.

The dialog was broken because of race condition between
https://codereview.chromium.org/1115993002 and
https://codereview.chromium.org/1129063003

BUG=488629
TEST=manually

Committed: https://crrev.com/d1b5d559c63656bb344519d18e4e995fd6a8e9f9
Cr-Commit-Position: refs/heads/master@{#330237}

[dzhioev (left Google), 2015-05-15 22:17:49]

dzhioev@chromium.org changed reviewers:
+ achuith@chromium.org

[achuithb, 2015-05-15 22:19:43]

lgtm

[dzhioev (left Google), 2015-05-15 22:22:59]

The CQ bit was checked by dzhioev@chromium.org

[commit-bot: I haz the power, 2015-05-15 22:24:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1124213004/20001

[commit-bot: I haz the power, 2015-05-15 23:52:07]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-18 11:29:24]

Patchset 2 (id:??) landed as
https://crrev.com/d1b5d559c63656bb344519d18e4e995fd6a8e9f9
Cr-Commit-Position: refs/heads/master@{#330237}