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

webrtc/sdk/BUILD.gn

 # Copyright 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("../webrtc.gni")
 if (is_ios) {
@@ skipping 13 matching lines @@
     include_dirs = [
       "objc/Framework/Classes",
       "objc/Framework/Headers",
     ]
   }
 
   rtc_static_library("rtc_sdk_common_objc") {
     deps = [
       "../base:rtc_base",
     ]
-    configs += [ "..:common_objc" ]
+    configs += [
+      "..:common_objc",
+      "//build/config/compiler:enable_arc",
+    ]
     public_configs = [ ":rtc_sdk_common_objc_config" ]
     sources = [
       "objc/Framework/Classes/NSString+StdString.h",
       "objc/Framework/Classes/NSString+StdString.mm",
       "objc/Framework/Classes/RTCDispatcher.m",
       "objc/Framework/Classes/RTCFieldTrials.mm",
       "objc/Framework/Classes/RTCLogging.mm",
       "objc/Framework/Classes/RTCMetrics.mm",
       "objc/Framework/Classes/RTCMetricsSampleInfo+Private.h",
       "objc/Framework/Classes/RTCMetricsSampleInfo.mm",
@@ skipping 168 matching lines @@
       sources += [
         "objc/Framework/Classes/RTCNSGLVideoView.m",
         "objc/Framework/Headers/WebRTC/RTCNSGLVideoView.h",
       ]
       libs = [
         "CoreMedia.framework",
         "OpenGL.framework",
       ]
     }
 
-    configs += [ "..:common_objc" ]
+    configs += [
+      "..:common_objc",
+      "//build/config/compiler:enable_arc",
+    ]
 
     public_configs = [ ":rtc_sdk_common_objc_config" ]
 
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
 
     libs += [ "AVFoundation.framework" ]
 
@@ skipping 118 matching lines @@
 
       libs = [
         "AVFoundation.framework",
         "AudioToolbox.framework",
         "CoreGraphics.framework",
         "CoreMedia.framework",
         "GLKit.framework",
         "VideoToolbox.framework",
       ]
 
-      configs += [ "..:common_objc" ]
+      configs += [
+        "..:common_objc",
+        "//build/config/compiler:enable_arc",
+      ]
 
       public_configs = [ ":rtc_sdk_common_objc_config" ]
 
       if (!build_with_chromium && is_clang) {
         # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163)
         configs -= [ "//build/config/clang:find_bad_constructs" ]
       }
     }
   }
 
   rtc_static_library("rtc_sdk_objc") {
     complete_static_lib = true
     deps = [
       ":rtc_sdk_peerconnection_objc",
       "//webrtc/system_wrappers:field_trial_default",
       "//webrtc/system_wrappers:metrics_default",
     ]
   }
 
   rtc_static_library("webrtc_h264_video_toolbox") {
     sources = [
       "objc/Framework/Classes/h264_video_toolbox_decoder.cc",
       "objc/Framework/Classes/h264_video_toolbox_decoder.h",
       "objc/Framework/Classes/h264_video_toolbox_encoder.h",
       "objc/Framework/Classes/h264_video_toolbox_encoder.mm",
       "objc/Framework/Classes/h264_video_toolbox_nalu.cc",
       "objc/Framework/Classes/h264_video_toolbox_nalu.h",
     ]
 
-    configs += [ "//webrtc:common_objc" ]
+    configs += [
+      "//webrtc:common_objc",
+      "//build/config/compiler:enable_arc",
+    ]
 
     deps = [
       ":rtc_sdk_common_objc",
     ]
 
     libs = [
       "CoreFoundation.framework",
       "CoreMedia.framework",
       "CoreVideo.framework",
       "VideoToolbox.framework",
     ]
 
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
 
     if (rtc_build_libyuv) {
       deps += [ "$rtc_libyuv_dir" ]
       public_deps = [
         "$rtc_libyuv_dir",
       ]
     } else {
       # Need to add a directory normally exported by libyuv.
       include_dirs = [ "$rtc_libyuv_dir/include" ]
     }
   }
 }