Add QuicStringPiece which is actually StringPiece.

net/quic/core/crypto/ephemeral_key_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_EPHEMERAL_KEY_SOURCE_H_
 #define NET_QUIC_CORE_CRYPTO_EPHEMERAL_KEY_SOURCE_H_
 
 #include <string>
 
-#include "base/strings/string_piece.h"
 #include "net/quic/core/quic_time.h"
 #include "net/quic/platform/api/quic_export.h"
+#include "net/quic/platform/api/quic_string_piece.h"
 
 namespace net {
 
 class KeyExchange;
 class QuicRandom;
 
 // EphemeralKeySource manages and rotates ephemeral keys as they can be reused
 // for several connections in a short space of time. Since the implementation
 // of this may involve locking or thread-local data, this interface abstracts
 // that away.
 class QUIC_EXPORT_PRIVATE EphemeralKeySource {
  public:
   virtual ~EphemeralKeySource() {}
 
   // CalculateForwardSecureKey generates an ephemeral public/private key pair
   // using the algorithm |key_exchange|, sets |*public_value| to the public key
   // and returns the shared key between |peer_public_value| and the private
   // key. |*public_value| will be sent to the peer to be used with the peer's
   // private key.
   virtual std::string CalculateForwardSecureKey(
       const KeyExchange* key_exchange,
       QuicRandom* rand,
       QuicTime now,
-      base::StringPiece peer_public_value,
+      QuicStringPiece peer_public_value,
       std::string* public_value) = 0;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_CRYPTO_EPHEMERAL_KEY_SOURCE_H_