Add QuicStringPiece which is actually StringPiece.

net/quic/core/crypto/curve25519_key_exchange_test.cc

 // 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.
 
 #include "net/quic/core/crypto/curve25519_key_exchange.h"
 
 #include <memory>
 
 #include "net/quic/core/crypto/quic_random.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using base::StringPiece;
 using std::string;
 
 namespace net {
 namespace test {
 
 // SharedKey just tests that the basic key exchange identity holds: that both
 // parties end up with the same key.
 TEST(Curve25519KeyExchange, SharedKey) {
   QuicRandom* const rand = QuicRandom::GetInstance();
 
   for (int i = 0; i < 5; i++) {
     const string alice_key(Curve25519KeyExchange::NewPrivateKey(rand));
     const string bob_key(Curve25519KeyExchange::NewPrivateKey(rand));
 
     std::unique_ptr<Curve25519KeyExchange> alice(
         Curve25519KeyExchange::New(alice_key));
     std::unique_ptr<Curve25519KeyExchange> bob(
         Curve25519KeyExchange::New(bob_key));
 
-    const StringPiece alice_public(alice->public_value());
-    const StringPiece bob_public(bob->public_value());
+    const QuicStringPiece alice_public(alice->public_value());
+    const QuicStringPiece bob_public(bob->public_value());
 
     string alice_shared, bob_shared;
     ASSERT_TRUE(alice->CalculateSharedKey(bob_public, &alice_shared));
     ASSERT_TRUE(bob->CalculateSharedKey(alice_public, &bob_shared));
     ASSERT_EQ(alice_shared, bob_shared);
   }
 }
 
 }  // namespace test
 }  // namespace net