Enforce SavePersistentPrefs in RestartJob path.
Enforce SavePersistentPrefs in RestartJob path.

Settings saved via ScheduleSavePersistentPrefs may be lost if exitted via chromeos::RestartJob.
Evidence of those losses were observed on debug build:
change language on new user pod and then start new incognito session: in ~20-30% cases changed language is lost.

BUG=chromium-os:13102
TEST=Manual

Review URL: http://codereview.chromium.org/6710001

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@78683 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser