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

webrtc/examples/BUILD.gn

Index: webrtc/examples/BUILD.gn
diff --git a/webrtc/examples/BUILD.gn b/webrtc/examples/BUILD.gn
index 24619d6f2e2a7b278d64e29500987ae5eb440ad6..ebe426f00c18cbcdb494747398c42a7bdf89c4f3 100644
--- a/webrtc/examples/BUILD.gn
+++ b/webrtc/examples/BUILD.gn
@@ -160,6 +160,7 @@
       "objc/AppRTCMobile/common/ARDUtilities.h",
       "objc/AppRTCMobile/common/ARDUtilities.m",
     ]
+    configs += [ "//build/config/compiler:enable_arc" ]
     public_configs = [ ":apprtc_common_config" ]
 
     deps = [
@@ -224,6 +225,7 @@
       "objc/AppRTCMobile/RTCSessionDescription+JSON.h",
       "objc/AppRTCMobile/RTCSessionDescription+JSON.m",
     ]
+    configs += [ "//build/config/compiler:enable_arc" ]
     public_configs = [ ":apprtc_signaling_config" ]
     deps = [
       ":apprtc_common",
@@ -256,6 +258,7 @@
         "objc/AppRTCMobile/ios/UIImage+ARDUtilities.h",
         "objc/AppRTCMobile/ios/UIImage+ARDUtilities.m",
       ]
+      configs += [ "//build/config/compiler:enable_arc" ]
 
       deps = [
         ":apprtc_common",
@@ -332,7 +335,10 @@
         "objc/AppRTCMobile/mac/APPRTCViewController.h",
         "objc/AppRTCMobile/mac/APPRTCViewController.m",
       ]
-      configs += [ "//webrtc:common_objc" ]
+      configs += [
+        "//webrtc:common_objc",
+        "//build/config/compiler:enable_arc",
+      ]
       deps = [
         ":apprtc_common",
         ":apprtc_signaling",
@@ -386,7 +392,10 @@
       "objc/AppRTCMobile/third_party/SocketRocket/SRWebSocket.h",
       "objc/AppRTCMobile/third_party/SocketRocket/SRWebSocket.m",
     ]
-    configs += [ ":socketrocket_warning_config" ]
+    configs += [
+      "//build/config/compiler:enable_arc",
+      ":socketrocket_warning_config",
+    ]
     public_configs = [ ":socketrocket_include_config" ]
 
     libs = [
@@ -419,6 +428,7 @@
           "//build/config/ios:xctest",
           "//third_party/ocmock",
         ]
+        configs += [ "//build/config/compiler:enable_arc" ]
       }
 
       rtc_ios_xctest_test("apprtcmobile_tests") {