Add QuicStringPiece which is actually StringPiece.

net/quic/chromium/crypto/proof_source_chromium.h

 // Copyright 2013 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_CHROMIUM_CRYPTO_PROOF_SOURCE_CHROMIUM_H_
 #define NET_QUIC_CHROMIUM_CRYPTO_PROOF_SOURCE_CHROMIUM_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 19 matching lines @@
   // timestamp may be loaded from |sct_path| if it is non-empty.
   bool Initialize(const base::FilePath& cert_path,
                   const base::FilePath& key_path,
                   const base::FilePath& sct_path);
 
   // ProofSource interface
   void GetProof(const QuicSocketAddress& server_ip,
                 const std::string& hostname,
                 const std::string& server_config,
                 QuicVersion quic_version,
-                base::StringPiece chlo_hash,
+                QuicStringPiece chlo_hash,
                 const QuicTagVector& connection_options,
                 std::unique_ptr<Callback> callback) override;
 
  private:
   bool GetProofInner(const QuicSocketAddress& server_ip,
                      const std::string& hostname,
                      const std::string& server_config,
                      QuicVersion quic_version,
-                     base::StringPiece chlo_hash,
+                     QuicStringPiece chlo_hash,
                      const QuicTagVector& connection_options,
                      QuicReferenceCountedPointer<ProofSource::Chain>* out_chain,
                      QuicCryptoProof* proof);
 
   std::unique_ptr<crypto::RSAPrivateKey> private_key_;
   QuicReferenceCountedPointer<ProofSource::Chain> chain_;
   std::string signed_certificate_timestamp_;
 
   DISALLOW_COPY_AND_ASSIGN(ProofSourceChromium);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CHROMIUM_CRYPTO_PROOF_SOURCE_CHROMIUM_H_