Add a data structure QuicMultipathTransmissionsMap which is not in use now.

net/net.gypi

 # 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.
 
 # This file is shared between the regular GYP build, the NaCl GYP build, and
 # the GN build. For GN support, it must have no conditionals or anything like
 # that beyond the simple one-level-deep dictionary of values.
 {
   'variables': {
     # Subset of net source files that are compiled for NaCl (net_nacl target).
@@ skipping 327 matching lines @@
       'quic/quic_fec_group_interface.cc',
       'quic/quic_fec_group_interface.h',
       'quic/quic_flags.cc',
       'quic/quic_flags.h',
       'quic/quic_flow_controller.cc',
       'quic/quic_flow_controller.h',
       'quic/quic_frame_list.cc',
       'quic/quic_frame_list.h',
       'quic/quic_framer.cc',
       'quic/quic_framer.h',
+      'quic/quic_multipath_transmissions_map.cc',
+      'quic/quic_multipath_transmissions_map.h',
       'quic/quic_packet_creator.cc',
       'quic/quic_packet_creator.h',
       'quic/quic_packet_generator.cc',
       'quic/quic_packet_generator.h',
       'quic/quic_packet_reader.cc',
       'quic/quic_packet_reader.h',
       'quic/quic_packet_writer.h',
       'quic/quic_protocol.cc',
       'quic/quic_protocol.h',
       'quic/quic_received_packet_manager.cc',
@@ skipping 1177 matching lines @@
       'quic/quic_crypto_client_stream_test.cc',
       'quic/quic_crypto_server_stream_test.cc',
       'quic/quic_crypto_stream_test.cc',
       'quic/quic_data_writer_test.cc',
       'quic/quic_fec_group_test.cc',
       'quic/quic_flow_controller_test.cc',
       'quic/quic_framer_test.cc',
       'quic/quic_headers_stream_test.cc',
       'quic/quic_http_stream_test.cc',
       'quic/quic_http_utils_test.cc',
+      'quic/quic_multipath_transmissions_map_test.cc',
       'quic/quic_network_transaction_unittest.cc',
       'quic/quic_packet_creator_test.cc',
       'quic/quic_packet_generator_test.cc',
       'quic/quic_protocol_test.cc',
       'quic/quic_received_packet_manager_test.cc',
       'quic/quic_reliable_client_stream_test.cc',
       'quic/quic_sent_entropy_manager_test.cc',
       'quic/quic_sent_packet_manager_test.cc',
       'quic/quic_server_id_test.cc',
       'quic/quic_session_test.cc',
@@ skipping 349 matching lines @@
       'docs/bug-triage.md',
       'docs/bug-triage-labels.md',
       'docs/bug-triage-suggested-workflow.md',
       'docs/code-patterns.md',
       'docs/life-of-a-url-request.md',
       'sdch/README.md',
     ],
     'net_docs_output_dir': '<(PRODUCT_DIR)/net/docs',
   }
 }