Show privet notifications only on platforms with rich notifications

Without rich notifications, the privet notifications are annoying and contain no
buttons. Enable them only for platforms with rich notifications.

BUG=297330

Review URL: https://chromiumcodereview.appspot.com/24335008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224941 0039d316-1c4b-4281-b951-d872f2087c98
Migrate DBus service constants from flimflam namespace to shill namespace.

All shill DBus service constants have been moved from the flimflam namespace to
the shill namespace. This CL makes the corresponding changes on the Chrome
side.

Related CLs:
  https://chromium-review.googlesource.com/#/c/170123/
  https://chromium-review.googlesource.com/#/c/170205/
  https://chromium-review.googlesource.com/#/c/170206/
  https://chromium-review.googlesource.com/#/c/170207/
  https://chromium-review.googlesource.com/#/c/170208/
  https://chromium-review.googlesource.com/#/c/170209/
  https://chromium-review.googlesource.com/#/c/170223/
  https://chromium-review.googlesource.com/#/c/170230/
  https://chromium-review.googlesource.com/#/c/170231/

BUG=295425
R=gspencer@chromium.org,gauravsh@chromium.org,stevenjb@chromium.org

Review URL: https://chromiumcodereview.appspot.com/24348002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224942 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224942