Add a new QuicFlagSaver class for saving/restoring the values of QUIC flags in tests.

net/quic/core/quic_framer_test.cc

 // 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.
 
 #include "net/quic/core/quic_framer.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <map>
@@ skipping 480 matching lines @@
                               const QuicFrames& frames) {
     return BuildUnsizedDataPacket(&framer_, header, frames);
   }
 
   QuicPacket* BuildDataPacket(const QuicPacketHeader& header,
                               const QuicFrames& frames,
                               size_t packet_size) {
     return BuildUnsizedDataPacket(&framer_, header, frames, packet_size);
   }
 
+  QuicFlagSaver flags_;  // Save/restore all QUIC flag values.
   test::TestEncrypter* encrypter_;
   test::TestDecrypter* decrypter_;
   QuicVersion version_;
   QuicTime start_;
   QuicFramer framer_;
   test::TestQuicVisitor visitor_;
   test::TestEntropyCalculator entropy_calculator_;
 };
 
 // Run all framer tests with all supported versions of QUIC.
@@ skipping 6676 matching lines @@
     'o',  ' ',  'w',  'o',
     'r',  'l',  'd',  '!',
   };
   // clang-format on
 
   QuicFramerFuzzFunc(packet, arraysize(packet));
 }
 
 }  // namespace test
 }  // namespace net