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

webrtc/sdk/objc/Framework/UnitTests/RTCPeerConnectionTest.mm

Index: webrtc/sdk/objc/Framework/UnitTests/RTCPeerConnectionTest.mm
diff --git a/webrtc/sdk/objc/Framework/UnitTests/RTCPeerConnectionTest.mm b/webrtc/sdk/objc/Framework/UnitTests/RTCPeerConnectionTest.mm
index bd2db305da7daf15cc727583a51f22f2d576bb4f..1797feabce077143a3a7615e8da534c3f2bedc24 100644
--- a/webrtc/sdk/objc/Framework/UnitTests/RTCPeerConnectionTest.mm
+++ b/webrtc/sdk/objc/Framework/UnitTests/RTCPeerConnectionTest.mm
@@ -53,11 +53,13 @@
   RTCMediaConstraints *contraints = [[RTCMediaConstraints alloc] initWithMandatoryConstraints:@{}
       optionalConstraints:nil];
   RTCPeerConnectionFactory *factory = [[RTCPeerConnectionFactory alloc] init];
-  RTCPeerConnection *peerConnection = [factory peerConnectionWithConfiguration:config
-      constraints:contraints delegate:nil];
-
-  RTCConfiguration *newConfig = peerConnection.configuration;
 
+  RTCConfiguration *newConfig;
+  @autoreleasepool {
+    RTCPeerConnection *peerConnection =
+        [factory peerConnectionWithConfiguration:config constraints:contraints delegate:nil];
+    newConfig = peerConnection.configuration;
+  }
   EXPECT_EQ([config.iceServers count], [newConfig.iceServers count]);
   RTCIceServer *newServer = newConfig.iceServers[0];
   RTCIceServer *origServer = config.iceServers[0];