Add QuicStringPiece which is actually StringPiece.

net/quic/platform/api/quic_url_utils.cc

 // Copyright (c) 2017 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/platform/api/quic_url_utils.h"
 
-using base::StringPiece;
 using std::string;
 
 namespace net {
 
 // static
-string QuicUrlUtils::HostName(StringPiece url) {
+string QuicUrlUtils::HostName(QuicStringPiece url) {
   return QuicUrlUtilsImpl::HostName(url);
 }
 
 // static
-bool QuicUrlUtils::IsValidUrl(StringPiece url) {
+bool QuicUrlUtils::IsValidUrl(QuicStringPiece url) {
   return QuicUrlUtilsImpl::IsValidUrl(url);
 }
 
 }  // namespace net