Remove unused warning suppression

webrtc/examples/BUILD.gn

 # Copyright (c) 2016 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("../build/webrtc.gni")
 if (is_android) {
@@ skipping 337 matching lines @@
     include_dirs = [ "objc/AppRTCMobile/third_party/SocketRocket" ]
   }
 
   config("socketrocket_warning_config") {
     # GN orders flags on a target before flags from configs. The default config
     # adds these flags so to cancel them out they need to come from a config and
     # cannot be on the target directly.
     cflags = [
       "-Wno-deprecated-declarations",
       "-Wno-nonnull",
-      "-Wno-objc-missing-property-synthesis",
       "-Wno-semicolon-before-method-body",
       "-Wno-unused-variable",
     ]
 
     cflags_objc = [
       # Enabled for cflags_objc in build/config/compiler/BUILD.gn.
       "-Wno-objc-missing-property-synthesis",
 
       # Hide the warning for SecRandomCopyBytes(), until we update to upstream.
       # https://bugs.chromium.org/p/webrtc/issues/detail?id=6396
@@ skipping 222 matching lines @@
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
 
     deps = [
       "../p2p:libstunprober",
       "../p2p:rtc_p2p",
       "../system_wrappers:field_trial_default",
     ]
   }
 }