Tweaks for new Objective-C API.
BUG=
Review URL: https://codereview.webrtc.org/1696673003
Cr-Commit-Position: refs/heads/master@{#11872}
diff --git a/webrtc/api/objc/RTCAVFoundationVideoSource.h b/webrtc/api/objc/RTCAVFoundationVideoSource.h
index 1fa19c5..e340444 100644
--- a/webrtc/api/objc/RTCAVFoundationVideoSource.h
+++ b/webrtc/api/objc/RTCAVFoundationVideoSource.h
@@ -26,7 +26,7 @@
@interface RTCAVFoundationVideoSource : RTCVideoSource
- (instancetype)initWithFactory:(RTCPeerConnectionFactory *)factory
- constraints:(RTCMediaConstraints *)constraints;
+ constraints:(nullable RTCMediaConstraints *)constraints;
/** Switches the camera being used (either front or back). */
@property(nonatomic, assign) BOOL useBackCamera;