Move WebContents.java and NavigationController.java to content_public

BUG=335690

Review URL: https://codereview.chromium.org/144583002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246439 0039d316-1c4b-4281-b951-d872f2087c98
[DevTools] Ensure docked DevTools window is focused when showing it.

We need to focus twice on Aura for some reason.
We also need to activate tab before showing/focusing DevTools in
case another tab is currently active.

BUG=318597

Review URL: https://codereview.chromium.org/144913004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246440 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246440