Add QuicStringPiece which is actually StringPiece.

net/quic/core/quic_client_session_base.cc

 // 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.
 
 #include "net/quic/core/quic_client_session_base.h"
 
 #include "net/quic/core/quic_client_promised_info.h"
 #include "net/quic/core/quic_flags.h"
 #include "net/quic/core/spdy_utils.h"
 #include "net/quic/platform/api/quic_logging.h"
 
-using base::StringPiece;
 using std::string;
 
 namespace net {
 
 QuicClientSessionBase::QuicClientSessionBase(
     QuicConnection* connection,
     QuicClientPushPromiseIndex* push_promise_index,
     const QuicConfig& config)
     : QuicSpdySession(connection, nullptr, config),
       push_promise_index_(push_promise_index),
@@ skipping 154 matching lines @@
                                              bool locally_reset) {
   QuicSpdySession::CloseStreamInner(stream_id, locally_reset);
   headers_stream()->MaybeReleaseSequencerBuffer();
 }
 
 bool QuicClientSessionBase::ShouldReleaseHeadersStreamSequencerBuffer() {
   return num_active_requests() == 0 && promised_by_id_.empty();
 }
 
 }  // namespace net