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

net/tools/quic/quic_client_session_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/tools/quic/quic_client_session.h"
 
 #include <vector>
 
 #include "base/strings/stringprintf.h"
 #include "net/base/ip_endpoint.h"
@@ skipping 18 matching lines @@
 using net::test::DefaultQuicConfig;
 using net::test::MockQuicConnection;
 using net::test::MockQuicConnectionHelper;
 using net::test::MockQuicSpdyClientStream;
 using net::test::PacketSavingConnection;
 using net::test::QuicConnectionPeer;
 using net::test::QuicPacketCreatorPeer;
 using net::test::QuicSpdySessionPeer;
 using net::test::SupportedVersions;
 using net::test::TestPeerIPAddress;
-using net::test::ValueRestore;
 using net::test::kClientDataStreamId1;
 using net::test::kServerDataStreamId1;
 using net::test::kTestPort;
 using std::string;
 using testing::AnyNumber;
 using testing::Invoke;
 using testing::Truly;
 using testing::_;
 
 namespace net {
@@ skipping 477 matching lines @@
   QuicClientPromisedInfo* promised =
       session_->GetPromisedById(promised_stream_id_);
   EXPECT_NE(promised, nullptr);
   EXPECT_NE(session_->GetPromisedByUrl(promise_url_), nullptr);
   EXPECT_EQ(session_->GetPromisedStream(promised_stream_id_), nullptr);
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net