Add QuicStringPiece which is actually StringPiece.

net/quic/platform/api/quic_string_piece.h

Index: net/quic/platform/api/quic_string_piece.h
diff --git a/net/quic/platform/api/quic_string_piece.h b/net/quic/platform/api/quic_string_piece.h
new file mode 100644
index 0000000000000000000000000000000000000000..d852429c845d3ec07b7e7f5006ec38439ea0dbe9
--- /dev/null
+++ b/net/quic/platform/api/quic_string_piece.h
@@ -0,0 +1,16 @@
+// 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.
+
+#ifndef NET_QUIC_PLATFORM_API_QUIC_STRING_PIECE_H_
+#define NET_QUIC_PLATFORM_API_QUIC_STRING_PIECE_H_
+
+#include "net/quic/platform/impl/quic_string_piece_impl.h"
+
+namespace net {
+
+using QuicStringPiece = QuicStringPieceImpl;
+
+}  // namespace net
+
+#endif  // NET_QUIC_PLATFORM_API_QUIC_STRING_PIECE_H_