remove module-wide warning suppression.

webrtc/modules/audio_device/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("../../webrtc.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
 }
 
 config("audio_device_config") {
   include_dirs = [
     "../include",
     "include",
     "dummy",  # Contains dummy audio device implementations.
   ]
-  if (is_ios) {
-    # GN orders flags on a target before flags from configs. In order to be able
-    # suppress the -Wthread-safety-analysis warning, it has come from a config
-    # and can't be on the target directly.
-    # TODO(tkchin): Remove after fixing
-    # https://bugs.chromium.org/p/webrtc/issues/detail?id=5748
-    cflags = [ "-Wno-thread-safety-analysis" ]
-  }
 }
 
 config("audio_device_warnings_config") {
   if (is_win && is_clang) {
     cflags = [
       # Disable warnings failing when compiling with Clang on Windows.
       # https://bugs.chromium.org/p/webrtc/issues/detail?id=5366
       "-Wno-bool-conversion",
       "-Wno-delete-non-virtual-dtor",
       "-Wno-logical-op-parentheses",
@@ skipping 314 matching lines @@
       "android/java/src/org/webrtc/voiceengine/WebRtcAudioManager.java",
       "android/java/src/org/webrtc/voiceengine/WebRtcAudioRecord.java",
       "android/java/src/org/webrtc/voiceengine/WebRtcAudioTrack.java",
       "android/java/src/org/webrtc/voiceengine/WebRtcAudioUtils.java",
     ]
     deps = [
       "//webrtc/base:base_java",
     ]
   }
 }