Fixed crash when PCF is destroyed before MediaSource/Track in ObjC

Bug: webrtc:9231
Change-Id: I31b86aa560f4ad230c9a94fedebebf320e0370a4
Reviewed-on: https://webrtc-review.googlesource.com/88221
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23981}

sdk/objc/Framework/UnitTests/RTCPeerConnectionFactory_xctest.m

@@ -8,6 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#import <WebRTC/RTCAudioSource.h>
 #import <WebRTC/RTCConfiguration.h>
 #import <WebRTC/RTCDataChannel.h>
 #import <WebRTC/RTCDataChannelConfiguration.h>
@@ -18,6 +19,7 @@
 #import <WebRTC/RTCRtpReceiver.h>
 #import <WebRTC/RTCRtpSender.h>
 #import <WebRTC/RTCRtpTransceiver.h>
+#import <WebRTC/RTCVideoSource.h>
 
 #import <XCTest/XCTest.h>
 
@@ -193,6 +195,74 @@
   XCTAssertTrue(true, "Expect test does not crash");
 }
 
+- (void)testAudioSourceLifetime {
+  @autoreleasepool {
+    RTCPeerConnectionFactory *factory;
+    RTCAudioSource *audioSource;
+
+    @autoreleasepool {
+      factory = [[RTCPeerConnectionFactory alloc] init];
+      audioSource = [factory audioSourceWithConstraints:nil];
+      XCTAssertNotNil(audioSource);
+      factory = nil;
+    }
+    audioSource = nil;
+  }
+
+  XCTAssertTrue(true, "Expect test does not crash");
+}
+
+- (void)testVideoSourceLifetime {
+  @autoreleasepool {
+    RTCPeerConnectionFactory *factory;
+    RTCVideoSource *videoSource;
+
+    @autoreleasepool {
+      factory = [[RTCPeerConnectionFactory alloc] init];
+      videoSource = [factory videoSource];
+      XCTAssertNotNil(videoSource);
+      factory = nil;
+    }
+    videoSource = nil;
+  }
+
+  XCTAssertTrue(true, "Expect test does not crash");
+}
+
+- (void)testAudioTrackLifetime {
+  @autoreleasepool {
+    RTCPeerConnectionFactory *factory;
+    RTCAudioTrack *audioTrack;
+
+    @autoreleasepool {
+      factory = [[RTCPeerConnectionFactory alloc] init];
+      audioTrack = [factory audioTrackWithTrackId:@"audioTrack"];
+      XCTAssertNotNil(audioTrack);
+      factory = nil;
+    }
+    audioTrack = nil;
+  }
+
+  XCTAssertTrue(true, "Expect test does not crash");
+}
+
+- (void)testVideoTrackLifetime {
+  @autoreleasepool {
+    RTCPeerConnectionFactory *factory;
+    RTCVideoTrack *videoTrack;
+
+    @autoreleasepool {
+      factory = [[RTCPeerConnectionFactory alloc] init];
+      videoTrack = [factory videoTrackWithSource:[factory videoSource] trackId:@"videoTrack"];
+      XCTAssertNotNil(videoTrack);
+      factory = nil;
+    }
+    videoTrack = nil;
+  }
+
+  XCTAssertTrue(true, "Expect test does not crash");
+}
+
 - (bool)negotiatePeerConnection:(RTCPeerConnection *)pc1
              withPeerConnection:(RTCPeerConnection *)pc2
              negotiationTimeout:(NSTimeInterval)timeout {