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

But this time with an ifdef CHROMEOS.

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

BUG=247229

Review URL: https://codereview.chromium.org/118703007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242256 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242256