GN: Enable ARC for Mac and iOS in rtc_* templates

webrtc/webrtc.gni

 # 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("//build/config/arm.gni")
 import("//build/config/features.gni")
@@ skipping 193 matching lines @@
 webrtc_root = get_path_info(".", "abspath")
 
 # Global configuration that should be applied to all WebRTC targets.
 # You normally shouldn't need to include this in your target as it's
 # automatically included when using the rtc_* templates.
 # It sets defines, include paths and compilation warnings accordingly,
 # both for WebRTC stand-alone builds and for the scenario when WebRTC
 # native code is built as part of Chromium.
 rtc_common_configs = [ webrtc_root + ":common_config" ]
 
+if (is_mac || is_ios) {
+  rtc_common_configs += [ "//build/config/compiler:enable_arc" ]
+}
+
 # Global public configuration that should be applied to all WebRTC targets. You
 # normally shouldn't need to include this in your target as it's automatically
 # included when using the rtc_* templates. It set the defines, include paths and
 # compilation warnings that should be propagated to dependents of the targets
 # depending on the target having this config.
 rtc_common_inherited_config = webrtc_root + ":common_inherited_config"
 
 # Common configs to remove or add in all rtc targets.
 rtc_remove_configs = []
 rtc_add_configs = rtc_common_configs
@@ skipping 141 matching lines @@
       configs += invoker.configs
       configs -= rtc_remove_configs
       configs -= invoker.suppressed_configs
       public_configs = [ rtc_common_inherited_config ]
       if (defined(invoker.public_configs)) {
         public_configs += invoker.public_configs
       }
     }
   }
 }