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

net/quic/core/quic_protocol.cc

Index: net/quic/core/quic_protocol.cc
diff --git a/net/quic/core/quic_protocol.cc b/net/quic/core/quic_protocol.cc
index 94445d5fa979af2bc8ba6a3aecca5cd47666a78f..b51f8eaa6003df8ef8f2e59f3e364ed1920acbf9 100644
--- a/net/quic/core/quic_protocol.cc
+++ b/net/quic/core/quic_protocol.cc
@@ -663,31 +663,6 @@ StringPiece QuicPacket::Plaintext(QuicVersion version) const {
                      length() - start_of_encrypted_data);
 }
 
-QuicVersionManager::QuicVersionManager(QuicVersionVector supported_versions)
-    : enable_version_36_(FLAGS_quic_enable_version_36_v3),
-      allowed_supported_versions_(supported_versions),
-      filtered_supported_versions_(
-          FilterSupportedVersions(supported_versions)) {}
-
-QuicVersionManager::~QuicVersionManager() {}
-
-const QuicVersionVector& QuicVersionManager::GetSupportedVersions() {
-  MaybeRefilterSupportedVersions();
-  return filtered_supported_versions_;
-}
-
-void QuicVersionManager::MaybeRefilterSupportedVersions() {
-  if (enable_version_36_ != FLAGS_quic_enable_version_36_v3) {
-    enable_version_36_ = FLAGS_quic_enable_version_36_v3;
-    RefilterSupportedVersions();
-  }
-}
-
-void QuicVersionManager::RefilterSupportedVersions() {
-  filtered_supported_versions_ =
-      FilterSupportedVersions(allowed_supported_versions_);
-}
-
 AckListenerWrapper::AckListenerWrapper(QuicAckListenerInterface* listener,
                                        QuicPacketLength data_length)
     : ack_listener(listener), length(data_length) {