Save display preference on boot.
Move the DisplayConfigurationObserver to shell delegate's PreInit which is the right place to do initialization that happens before Shell::Init.

BUG=332852

Review URL: https://codereview.chromium.org/137193004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245098 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245098