Tracking rbe tools with a GN target

webrtc/modules/remote_bitrate_estimator/tools/bwe_rtp.cc

 /*
  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 61 matching lines @@
                                 char** argv,
                                 webrtc::Clock* clock,
                                 webrtc::RemoteBitrateObserver* observer,
                                 webrtc::test::RtpFileReader** rtp_reader,
                                 webrtc::RtpHeaderParser** parser,
                                 webrtc::RemoteBitrateEstimator** estimator,
                                 std::string* estimator_used) {
   if (rtc::FlagList::SetFlagsFromCommandLine(&argc, argv, true)) {
     return 1;
   }
-  if (FLAG_help) {
+  if (flags::FLAG_help) {
     rtc::FlagList::Print(nullptr, false);
     return 0;
   }
   std::string filename = flags::InputFile();
 
   std::set<uint32_t> ssrc_filter = flags::SsrcFilter();
   fprintf(stderr, "Filter on SSRC: ");
   for (auto& s : ssrc_filter) {
     fprintf(stderr, "0x%08x, ", s);
   }
@@ skipping 41 matching lines @@
             new webrtc::RemoteBitrateEstimatorSingleStream(observer, clock);
           *estimator_used = "RemoteBitrateEstimator";
           break;
         }
       default:
         assert(false);
     }
   }
   return true;
 }