Rename NavigationController -> ServiceWorker

This is just a bunch of perl search 'n replace, and a little hand-editing
to keep it compiling.

BUG=

Review URL: https://chromiumcodereview.appspot.com/23447049

git-svn-id: svn://svn.chromium.org/blink/trunk@158156 bbb929c8-8fbe-4397-9dbb-9b2b20218538