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

net/quic/core/quic_protocol_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_protocol.h"
 
 #include <sstream>
 
 #include "base/stl_util.h"
 #include "net/quic/core/quic_flags.h"
@@ skipping 267 matching lines @@
 
 TEST(QuicProtocolTest, PathCloseFrameToString) {
   QuicPathCloseFrame frame;
   frame.path_id = 1;
   std::ostringstream stream;
   stream << frame;
   EXPECT_EQ("{ path_id: 1 }\n", stream.str());
 }
 
 TEST(QuicProtocolTest, FilterSupportedVersions) {
-  ValueRestore<bool> old_v35_flag(&FLAGS_quic_enable_version_35,
-                                  FLAGS_quic_enable_version_35);
-  ValueRestore<bool> old_v36_flag(&FLAGS_quic_enable_version_36,
-                                  FLAGS_quic_enable_version_36);
-  ValueRestore<bool> old_v36_2_flag(&FLAGS_quic_enable_version_36_v2,
-                                    FLAGS_quic_enable_version_36_v2);
+  QuicFlagSaver flags;
   QuicVersionVector all_versions = {
       QUIC_VERSION_30, QUIC_VERSION_31, QUIC_VERSION_32, QUIC_VERSION_33,
       QUIC_VERSION_34, QUIC_VERSION_35, QUIC_VERSION_36};
 
   FLAGS_quic_disable_pre_32 = true;
   FLAGS_quic_enable_version_35 = false;
   FLAGS_quic_enable_version_36_v2 = false;
 
   QuicVersionVector filtered_versions = FilterSupportedVersions(all_versions);
   ASSERT_EQ(3u, filtered_versions.size());
   EXPECT_EQ(QUIC_VERSION_32, filtered_versions[0]);
   EXPECT_EQ(QUIC_VERSION_33, filtered_versions[1]);
   EXPECT_EQ(QUIC_VERSION_34, filtered_versions[2]);
 }
 
 TEST(QuicProtocolTest, QuicVersionManager) {
-  ValueRestore<bool> old_v35_flag(&FLAGS_quic_enable_version_35,
-                                  FLAGS_quic_enable_version_35);
-  ValueRestore<bool> old_v36_2_flag(&FLAGS_quic_enable_version_36_v2,
-                                    FLAGS_quic_enable_version_36_v2);
+  QuicFlagSaver flags;
   FLAGS_quic_enable_version_35 = false;
   FLAGS_quic_enable_version_36_v2 = false;
   QuicVersionManager manager(AllSupportedVersions());
   EXPECT_EQ(FilterSupportedVersions(AllSupportedVersions()),
             manager.GetSupportedVersions());
   FLAGS_quic_enable_version_35 = true;
   FLAGS_quic_enable_version_36_v2 = true;
   EXPECT_EQ(FilterSupportedVersions(AllSupportedVersions()),
             manager.GetSupportedVersions());
   EXPECT_EQ(QUIC_VERSION_36, manager.GetSupportedVersions()[0]);
@@ skipping 145 matching lines @@
   EXPECT_EQ(2u, queue.NumIntervals());
   EXPECT_TRUE(queue.Contains(10));
   EXPECT_TRUE(queue.Contains(11));
   EXPECT_TRUE(queue.Contains(20));
   EXPECT_TRUE(queue.Contains(21));
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net