Remove remaining mentions of gflags

rtc_tools/BUILD.gn

 # 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.
 
 import("//third_party/protobuf/proto_library.gni")
 import("../webrtc.gni")
@@ skipping 216 matching lines @@
         "//build/config:exe_and_shlib_deps",
       ]
       public_deps = [
         ":chart_proto",
         "../logging:rtc_event_log_parser",
       ]
     }
   }
 }
 
-# Exclude tools depending on gflags since that's not available in Chromium.
 if (rtc_include_tests) {
   if (rtc_enable_protobuf) {
     rtc_executable("event_log_visualizer") {
       testonly = true
       sources = [
         "event_log_visualizer/main.cc",
       ]
 
       if (!build_with_chromium && is_clang) {
         # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
@@ skipping 101 matching lines @@
       ]
       outputs = [
         "$root_build_dir/{{source_file_part}}",
       ]
       deps = [
         "../logging:rtc_event_log_proto",
       ]
     }
   }
 }