Add support for field trial group to relax missing via header bypass logic.

components/data_reduction_proxy.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.
 
 
 {
   'targets': [
     {
       # GN version: //components/data_reduction_proxy/core/browser
       'target_name': 'data_reduction_proxy_core_browser',
@@ skipping 14 matching lines @@
         'data_reduction_proxy_core_common',
         'pref_registry',
       ],
       'include_dirs': [
         '..',
       ],
       'sources': [
         # Note: sources list duplicated in GN build.
         'data_reduction_proxy/core/browser/data_reduction_proxy_auth_request_handler.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_auth_request_handler.h',
+        'data_reduction_proxy/core/browser/data_reduction_proxy_bypass_protocol.cc',
+        'data_reduction_proxy/core/browser/data_reduction_proxy_bypass_protocol.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_configurator.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_configurator.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_delegate.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_delegate.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_interceptor.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_interceptor.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_metrics.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_metrics.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_prefs.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_prefs.h',
-        'data_reduction_proxy/core/browser/data_reduction_proxy_protocol.cc',
-        'data_reduction_proxy/core/browser/data_reduction_proxy_protocol.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_settings.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_settings.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_statistics_prefs.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_statistics_prefs.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_tamper_detection.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_tamper_detection.h',
         'data_reduction_proxy/core/browser/data_reduction_proxy_usage_stats.cc',
         'data_reduction_proxy/core/browser/data_reduction_proxy_usage_stats.h',
       ],
     },
@@ skipping 78 matching lines @@
           'includes': [
             '../build/util/version.gypi',
           ],
         },
       ],
     },
 
   ],
 }