Remove PathCloseFrame, QuicPathId, DefaultPathId and InvalidPathId.

net/quic/core/quic_framer_test.cc

Index: net/quic/core/quic_framer_test.cc
diff --git a/net/quic/core/quic_framer_test.cc b/net/quic/core/quic_framer_test.cc
index b9294f112ddff246ee3aa19a2a35b3e23dcb1cb7..6115ab674c9625806cd919d17e4e21c2c2277e0e 100644
--- a/net/quic/core/quic_framer_test.cc
+++ b/net/quic/core/quic_framer_test.cc
@@ -262,11 +262,6 @@ class TestQuicVisitor : public QuicFramerVisitorInterface {
     return true;
   }
 
-  bool OnPathCloseFrame(const QuicPathCloseFrame& frame) override {
-    path_close_frame_ = frame;
-    return true;
-  }
-
   // Counters from the visitor_ callbacks.
   int error_count_;
   int version_mismatch_;
@@ -290,7 +285,6 @@ class TestQuicVisitor : public QuicFramerVisitorInterface {
   QuicGoAwayFrame goaway_frame_;
   QuicWindowUpdateFrame window_update_frame_;
   QuicBlockedFrame blocked_frame_;
-  QuicPathCloseFrame path_close_frame_;
   std::vector<std::unique_ptr<string>> stream_data_;
 };