Remove PathCloseFrame, QuicPathId, DefaultPathId and InvalidPathId.

net/quic/core/quic_constants.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_QUIC_CORE_QUIC_CONSTANTS_H_
 #define NET_QUIC_CORE_QUIC_CONSTANTS_H_
 
 #include <stddef.h>
 
 #include <cstdint>
@@ skipping 153 matching lines @@
 //   if (exponent == 0) value = mantissa;
 //   else value = (mantissa | 1 << 11) << (exponent - 1)
 const int kUFloat16ExponentBits = 5;
 const int kUFloat16MaxExponent = (1 << kUFloat16ExponentBits) - 2;     // 30
 const int kUFloat16MantissaBits = 16 - kUFloat16ExponentBits;          // 11
 const int kUFloat16MantissaEffectiveBits = kUFloat16MantissaBits + 1;  // 12
 const uint64_t kUFloat16MaxValue =  // 0x3FFC0000000
     ((UINT64_C(1) << kUFloat16MantissaEffectiveBits) - 1)
     << kUFloat16MaxExponent;
 
-// Default path ID.
-const QuicPathId kDefaultPathId = 0;
-// Invalid path ID.
-const QuicPathId kInvalidPathId = 0xff;
-
 // kDiversificationNonceSize is the size, in bytes, of the nonce that a server
 // may set in the packet header to ensure that its INITIAL keys are not
 // duplicated.
 const size_t kDiversificationNonceSize = 32;
 
 // The largest gap in packets we'll accept without closing the connection.
 // This will likely have to be tuned.
 const QuicPacketNumber kMaxPacketGap = 5000;
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_QUIC_CONSTANTS_H_