Move QuicVersionManager into standalone .h/.cc. No behavior change.

net/quic/core/quic_version_manager_test.cc

+// Copyright (c) 2016 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_version_manager.h"
+
+#include "net/quic/core/quic_flags.h"
+#include "net/quic/core/quic_versions.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace net {
+namespace test {
+namespace {
+
+TEST(QuicVersionManagerTest, QuicVersionManager) {
+  FLAGS_quic_enable_version_36_v3 = false;
+  QuicVersionManager manager(AllSupportedVersions());
+  EXPECT_EQ(FilterSupportedVersions(AllSupportedVersions()),
+            manager.GetSupportedVersions());
+  FLAGS_quic_enable_version_36_v3 = true;
+  EXPECT_EQ(FilterSupportedVersions(AllSupportedVersions()),
+            manager.GetSupportedVersions());
+  EXPECT_EQ(QUIC_VERSION_36, manager.GetSupportedVersions()[0]);
+  EXPECT_EQ(QUIC_VERSION_35, manager.GetSupportedVersions()[1]);
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace net