Revert "Share NetworkingPrivateEventRouter between profile and it's incognito version"

Reverting this so I can relandig it with ifdef CHROME_OS (as having the ifdef
is condition for the change to be considered for merge back to 32).

original revision: http://crrev.com/237699

BUG=247229

Review URL: https://codereview.chromium.org/119993003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242235 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242235