net: Update the include paths of base/string_piece.h to its new location.

net/spdy/spdy_credential_builder.cc

 // Copyright (c) 2012 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/spdy/spdy_credential_builder.h"
 
 #include "base/logging.h"
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 #include "crypto/ec_private_key.h"
 #include "crypto/ec_signature_creator.h"
 #include "net/base/net_errors.h"
 #include "net/cert/asn1_util.h"
 #include "net/socket/ssl_client_socket.h"
 #include "net/spdy/spdy_framer.h"
 #include "net/ssl/server_bound_cert_service.h"
 
 namespace net {
 
@@ skipping 62 matching lines @@
 std::string SpdyCredentialBuilder::GetCredentialSecret(
     const std::string& tls_unique) {
   const char prefix[] = "SPDY CREDENTIAL ChannelID\0client -> server";
   std::string secret(prefix, arraysize(prefix));
   secret.append(tls_unique);
 
   return secret;
 }
 
 }  // namespace net