Introduce CrosBrowserWithOOBE, which exposes an oobe property.

This is only visible when the create_browser_with_oobe browser option is specified.

BUG=294183
TEST=manual

Review URL: https://codereview.chromium.org/23619077

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226476 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226476