Remove unnecessary chrome/ includes from chrome/browser/managed_mode/.

BUG=313377

Review URL: https://codereview.chromium.org/68533005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234534 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234534