Remove PathCloseFrame, QuicPathId, DefaultPathId and InvalidPathId.

net/tools/quic/quic_dispatcher.cc

Index: net/tools/quic/quic_dispatcher.cc
diff --git a/net/tools/quic/quic_dispatcher.cc b/net/tools/quic/quic_dispatcher.cc
index 801e1f2759ee33584723d612791db7e9fd8d041d..303a597a9e18b22259e10d7bf3fbbd0d814a632f 100644
--- a/net/tools/quic/quic_dispatcher.cc
+++ b/net/tools/quic/quic_dispatcher.cc
@@ -626,11 +626,6 @@ bool QuicDispatcher::OnBlockedFrame(const QuicBlockedFrame& frame) {
   return false;
 }
 
-bool QuicDispatcher::OnPathCloseFrame(const QuicPathCloseFrame& frame) {
-  DCHECK(false);
-  return false;
-}
-
 void QuicDispatcher::OnPacketComplete() {
   DCHECK(false);
 }