Remove the tracing cache backend.

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 456 matching lines @@
       'disk_cache/simple/simple_index_file_posix.cc',
       'disk_cache/simple/simple_index_file_win.cc',
       'disk_cache/simple/simple_net_log_parameters.cc',
       'disk_cache/simple/simple_net_log_parameters.h',
       'disk_cache/simple/simple_synchronous_entry.cc',
       'disk_cache/simple/simple_synchronous_entry.h',
       'disk_cache/simple/simple_util.cc',
       'disk_cache/simple/simple_util.h',
       'disk_cache/simple/simple_version_upgrade.cc',
       'disk_cache/simple/simple_version_upgrade.h',
-      'disk_cache/tracing/tracing_cache_backend.cc',
-      'disk_cache/tracing/tracing_cache_backend.h',
       'dns/address_sorter.h',
       'dns/address_sorter_posix.cc',
       'dns/address_sorter_posix.h',
       'dns/address_sorter_win.cc',
       'dns/dns_client.cc',
       'dns/dns_client.h',
       'dns/dns_config_service.cc',
       'dns/dns_config_service.h',
       'dns/dns_config_service_posix.cc',
       'dns/dns_config_service_posix.h',
@@ skipping 1248 matching lines @@
       'tools/quic/test_tools/quic_test_client.h',
       'tools/quic/test_tools/quic_test_utils.cc',
       'tools/quic/test_tools/quic_test_utils.h',
       'tools/quic/test_tools/server_thread.h',
       'tools/quic/test_tools/server_thread.cc',
       'tools/quic/test_tools/simple_client.h',
       'tools/quic/test_tools/simple_client.cc',
     ],
   }
 }