Mark public ObjC APIs as explicitly visible.
BUG=
Review URL: https://codereview.webrtc.org/1899573002
Cr-Commit-Position: refs/heads/master@{#12431}
diff --git a/webrtc/api/objc/RTCVideoTrack.h b/webrtc/api/objc/RTCVideoTrack.h
index a7b6f0c..ff4196e 100644
--- a/webrtc/api/objc/RTCVideoTrack.h
+++ b/webrtc/api/objc/RTCVideoTrack.h
@@ -10,12 +10,15 @@
#import "webrtc/api/objc/RTCMediaStreamTrack.h"
+#import "webrtc/base/objc/RTCMacros.h"
+
NS_ASSUME_NONNULL_BEGIN
@protocol RTCVideoRenderer;
@class RTCPeerConnectionFactory;
@class RTCVideoSource;
+RTC_EXPORT
@interface RTCVideoTrack : RTCMediaStreamTrack
/** The video source for this video track. */