Move quic_flags.h from net/quic/core to net/quic/platform and split into api and impl.

net/quic/core/quic_version_manager_test.cc

Index: net/quic/core/quic_version_manager_test.cc
diff --git a/net/quic/core/quic_version_manager_test.cc b/net/quic/core/quic_version_manager_test.cc
index 31d864d0f6fc095382d20b148900715e6095b446..05691b55e8d6e61f169264b9bd2c9b285e1a6134 100644
--- a/net/quic/core/quic_version_manager_test.cc
+++ b/net/quic/core/quic_version_manager_test.cc
@@ -4,8 +4,8 @@
 
 #include "net/quic/core/quic_version_manager.h"
 
-#include "net/quic/core/quic_flags.h"
 #include "net/quic/core/quic_versions.h"
+#include "net/quic/platform/api/quic_flags.h"
 #include "net/quic/test_tools/quic_test_utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -30,7 +30,7 @@ TEST(QuicVersionManagerTest, QuicVersionManager) {
   EXPECT_EQ(QUIC_VERSION_36, manager.GetSupportedVersions()[2]);
   EXPECT_EQ(QUIC_VERSION_35, manager.GetSupportedVersions()[3]);
 
-  base::SetFlag(&FLAGS_quic_enable_version_39, true);
+  SetQuicFlag(&FLAGS_quic_enable_version_39, true);
   EXPECT_EQ(FilterSupportedVersions(AllSupportedVersions()),
             manager.GetSupportedVersions());
   ASSERT_EQ(5u, manager.GetSupportedVersions().size());