Add a new QUIC ChloExtractor class used by the QuicProxyDispatcher to extract CHLO message from pac…

net/tools/quic/chlo_extractor.h

+// 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.
+
+#ifndef NET_TOOLS_QUIC_CHLO_EXTRACTOR_H_
+#define NET_TOOLS_QUIC_CHLO_EXTRACTOR_H_
+
+#include "net/quic/crypto/crypto_handshake_message.h"
+#include "net/quic/quic_protocol.h"
+
+namespace net {
+
+// A utility for extracting QUIC Client Hello messages from packets,
+// without needs to spin up a full QuicSession.
+class ChloExtractor {
+ public:
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    // Called when a CHLO message is found in the packets.
+    virtual void OnChlo(QuicVersion version,
+                        QuicConnectionId connection_id,
+                        const CryptoHandshakeMessage& chlo) = 0;
+  };
+
+  // Extracts a CHLO message from |packet| and invokes the OnChlo method
+  // of |delegate|. Return true if a CHLO message was found, and false
+  // otherwise.
+  static bool Extract(const QuicEncryptedPacket& packet,
+                      const QuicVersionVector& versions,
+                      Delegate* delegate);
+
+  ChloExtractor(ChloExtractor&) = delete;
+  ChloExtractor operator=(const ChloExtractor&) = delete;
+};
+
+}  // namespace net
+
+#endif  // NET_TOOLS_QUIC_CHLO_EXTRACTOR_H_