Add QuicStringPiece which is actually StringPiece.

net/quic/core/crypto/p256_key_exchange.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_P256_KEY_EXCHANGE_H_
 #define NET_QUIC_CORE_CRYPTO_P256_KEY_EXCHANGE_H_
 
 #include <cstdint>
 #include <string>
 
 #include "base/macros.h"
-#include "base/strings/string_piece.h"
 #include "net/quic/core/crypto/key_exchange.h"
 #include "net/quic/platform/api/quic_export.h"
+#include "net/quic/platform/api/quic_string_piece.h"
 #include "third_party/boringssl/src/include/openssl/base.h"
 
 namespace net {
 
 // P256KeyExchange implements a KeyExchange using elliptic-curve
 // Diffie-Hellman on NIST P-256.
 class QUIC_EXPORT_PRIVATE P256KeyExchange : public KeyExchange {
  public:
   ~P256KeyExchange() override;
 
   // New creates a new key exchange object from a private key. If
   // |private_key| is invalid, nullptr is returned.
-  static P256KeyExchange* New(base::StringPiece private_key);
+  static P256KeyExchange* New(QuicStringPiece private_key);
 
   // |NewPrivateKey| returns a private key, suitable for passing to |New|.
   // If |NewPrivateKey| can't generate a private key, it returns an empty
   // string.
   static std::string NewPrivateKey();
 
   // KeyExchange interface.
   KeyExchange* NewKeyPair(QuicRandom* rand) const override;
-  bool CalculateSharedKey(base::StringPiece peer_public_value,
+  bool CalculateSharedKey(QuicStringPiece peer_public_value,
                           std::string* shared_key) const override;
-  base::StringPiece public_value() const override;
+  QuicStringPiece public_value() const override;
   QuicTag tag() const override;
 
  private:
   enum {
     // A P-256 field element consists of 32 bytes.
     kP256FieldBytes = 32,
     // A P-256 point in uncompressed form consists of 0x04 (to denote
     // that the point is uncompressed) followed by two, 32-byte field
     // elements.
     kUncompressedP256PointBytes = 1 + 2 * kP256FieldBytes,
     // The first byte in an uncompressed P-256 point.
     kUncompressedECPointForm = 0x04,
   };
 
   // P256KeyExchange wraps |private_key|, and expects |public_key| consists of
   // |kUncompressedP256PointBytes| bytes.
   P256KeyExchange(bssl::UniquePtr<EC_KEY> private_key,
                   const uint8_t* public_key);
 
   bssl::UniquePtr<EC_KEY> private_key_;
   // The public key stored as an uncompressed P-256 point.
   uint8_t public_key_[kUncompressedP256PointBytes];
 
   DISALLOW_COPY_AND_ASSIGN(P256KeyExchange);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_CRYPTO_P256_KEY_EXCHANGE_H_