Remove PathCloseFrame, QuicPathId, DefaultPathId and InvalidPathId.

net/quic/core/quic_connection.h

Index: net/quic/core/quic_connection.h
diff --git a/net/quic/core/quic_connection.h b/net/quic/core/quic_connection.h
index f38adabd747e28b60573752e3fa6b2892adcc290..e5bf4ca91689f3a56690f442ff0659f95234d9eb 100644
--- a/net/quic/core/quic_connection.h
+++ b/net/quic/core/quic_connection.h
@@ -229,9 +229,6 @@ class QUIC_EXPORT_PRIVATE QuicConnectionDebugVisitor
   // Called when a BlockedFrame has been parsed.
   virtual void OnBlockedFrame(const QuicBlockedFrame& frame) {}
 
-  // Called when a PathCloseFrame has been parsed.
-  virtual void OnPathCloseFrame(const QuicPathCloseFrame& frame) {}
-
   // Called when a public reset packet has been received.
   virtual void OnPublicResetPacket(const QuicPublicResetPacket& packet) {}
 
@@ -445,7 +442,6 @@ class QUIC_EXPORT_PRIVATE QuicConnection
   bool OnGoAwayFrame(const QuicGoAwayFrame& frame) override;
   bool OnWindowUpdateFrame(const QuicWindowUpdateFrame& frame) override;
   bool OnBlockedFrame(const QuicBlockedFrame& frame) override;
-  bool OnPathCloseFrame(const QuicPathCloseFrame& frame) override;
   void OnPacketComplete() override;
 
   // QuicConnectionCloseDelegateInterface