Remove unused QuicDecrypter::Decrypt method and implementations.

net/quic/crypto/null_decrypter.h

 // 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.
 
 #ifndef NET_QUIC_CRYPTO_NULL_DECRYPTER_H_
 #define NET_QUIC_CRYPTO_NULL_DECRYPTER_H_
 
 #include "base/compiler_specific.h"
 #include "net/base/net_export.h"
 #include "net/quic/crypto/quic_decrypter.h"
 
 namespace net {
 
 class QuicDataReader;
 
 // A NullDecrypter is a QuicDecrypter used before a crypto negotiation
 // has occurred.  It does not actually decrypt the payload, but does
 // verify a hash (fnv128) over both the payload and associated data.
 class NET_EXPORT_PRIVATE NullDecrypter : public QuicDecrypter {
  public:
   NullDecrypter();
   ~NullDecrypter() override {}
 
   // QuicDecrypter implementation
   bool SetKey(base::StringPiece key) override;
   bool SetNoncePrefix(base::StringPiece nonce_prefix) override;
-  bool Decrypt(base::StringPiece nonce,
-               base::StringPiece associated_data,
-               base::StringPiece ciphertext,
-               unsigned char* output,
-               size_t* output_length) override;
   QuicData* DecryptPacket(QuicPacketSequenceNumber sequence_number,
                           base::StringPiece associated_data,
                           base::StringPiece ciphertext) override;
   base::StringPiece GetKey() const override;
   base::StringPiece GetNoncePrefix() const override;
 
  private:
   bool ReadHash(QuicDataReader* reader, uint128* hash);
   uint128 ComputeHash(const std::string& data) const;
 
   DISALLOW_COPY_AND_ASSIGN(NullDecrypter);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CRYPTO_NULL_DECRYPTER_H_