Add QuicStringPiece which is actually StringPiece.

net/quic/core/quic_versions.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/quic/core/quic_versions.h"
 
-#include "base/strings/string_piece.h"
 #include "net/quic/core/quic_error_codes.h"
 #include "net/quic/core/quic_flags.h"
 #include "net/quic/core/quic_tag.h"
 #include "net/quic/core/quic_types.h"
 #include "net/quic/platform/api/quic_logging.h"
 
-using base::StringPiece;
 using std::string;
 
 namespace net {
 
 QuicVersionVector AllSupportedVersions() {
   QuicVersionVector supported_versions;
   for (size_t i = 0; i < arraysize(kSupportedQuicVersions); ++i) {
     supported_versions.push_back(kSupportedQuicVersions[i]);
   }
   return supported_versions;
@@ skipping 97 matching lines @@
   for (size_t i = 0; i < versions.size(); ++i) {
     if (i != 0) {
       result.append(",");
     }
     result.append(QuicVersionToString(versions[i]));
   }
   return result;
 }
 
 }  // namespace net