Revert "Merge branch 'proto_nav'"

This reverts commit ae8230816a8d4dd8aee20dfa8d67e203f3843127, reversing
changes made to 75d259acb1fb6435753237994bcfd432a1acd27e.
Revert b175204..7f816ca

This rolls back to commit b175204b0257ddc555a05697646a43e41bf8cf5f.
Revert "Merge branch 'proto_nav'"

This reverts commit ae8230816a8d4dd8aee20dfa8d67e203f3843127, reversing
changes made to 75d259acb1fb6435753237994bcfd432a1acd27e.