When a navigation is initiated by the Web Content process, the navigation parameter passed to the navigation delegate is nil.
Created attachment 234142 [details] Attach navigationID and create WKNavigation at action policy decision time if needed
Created attachment 234147 [details] Attach navigationID and create WKNavigation at action policy decision time if needed
Created attachment 234170 [details] Attach navigationID and create WKNavigation at action policy decision time if needed
Created attachment 234183 [details] Attach navigationID and create WKNavigation at action policy decision time if needed
Fixed in <http://trac.webkit.org/r170660>.