Add QuicStringPiece which is actually StringPiece.

net/quic/chromium/crypto/channel_id_chromium.h

 // Copyright 2014 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_CHANNEL_ID_CHROMIUM_H_
 #define NET_QUIC_CHROMIUM_CRYPTO_CHANNEL_ID_CHROMIUM_H_
 
 #include <map>
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "net/base/net_export.h"
 #include "net/quic/core/crypto/channel_id.h"
+#include "net/quic/platform/api/quic_string_piece.h"
 
 namespace crypto {
 class ECPrivateKey;
 }  // namespace crypto
 
 namespace net {
 
 class ChannelIDService;
 
 class NET_EXPORT_PRIVATE ChannelIDKeyChromium : public ChannelIDKey {
  public:
   explicit ChannelIDKeyChromium(
       std::unique_ptr<crypto::ECPrivateKey> ec_private_key);
   ~ChannelIDKeyChromium() override;
 
   // ChannelIDKey interface
-  bool Sign(base::StringPiece signed_data,
+  bool Sign(QuicStringPiece signed_data,
             std::string* out_signature) const override;
   std::string SerializeKey() const override;
 
  private:
   std::unique_ptr<crypto::ECPrivateKey> ec_private_key_;
 };
 
 // ChannelIDSourceChromium implements the QUIC ChannelIDSource interface.
 class ChannelIDSourceChromium : public ChannelIDSource {
  public:
@@ skipping 15 matching lines @@
 
   // The service for retrieving Channel ID keys.
   ChannelIDService* const channel_id_service_;
 
   DISALLOW_COPY_AND_ASSIGN(ChannelIDSourceChromium);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CHROMIUM_CRYPTO_CHANNEL_ID_CHROMIUM_H_