Add QuicStringPiece which is actually StringPiece.

net/quic/core/crypto/proof_source.h

 // Copyright (c) 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_CORE_CRYPTO_PROOF_SOURCE_H_
 #define NET_QUIC_CORE_CRYPTO_PROOF_SOURCE_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "net/quic/core/crypto/quic_crypto_proof.h"
 #include "net/quic/core/quic_packets.h"
 #include "net/quic/platform/api/quic_export.h"
 #include "net/quic/platform/api/quic_reference_counted.h"
 #include "net/quic/platform/api/quic_socket_address.h"
+#include "net/quic/platform/api/quic_string_piece.h"
 
 namespace net {
 
 // ProofSource is an interface by which a QUIC server can obtain certificate
 // chains and signatures that prove its identity.
 class QUIC_EXPORT_PRIVATE ProofSource {
  public:
   // Chain is a reference-counted wrapper for a vector of stringified
   // certificates.
   struct QUIC_EXPORT_PRIVATE Chain : public QuicReferenceCounted {
@@ skipping 63 matching lines @@
   // |hostname| may be empty to signify that a default certificate should be
   // used.
   //
   // This function may be called concurrently.
   //
   // Callers should expect that |callback| might be invoked synchronously.
   virtual void GetProof(const QuicSocketAddress& server_address,
                         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) = 0;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_CRYPTO_PROOF_SOURCE_H_