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/RTCSessionDescription.h b/webrtc/api/objc/RTCSessionDescription.h
index 2635633..de927cf 100644
--- a/webrtc/api/objc/RTCSessionDescription.h
+++ b/webrtc/api/objc/RTCSessionDescription.h
@@ -10,6 +10,8 @@
#import <Foundation/Foundation.h>
+#import "webrtc/base/objc/RTCMacros.h"
+
/**
* Represents the session description type. This exposes the same types that are
* in C++, which doesn't include the rollback type that is in the W3C spec.
@@ -22,6 +24,7 @@
NS_ASSUME_NONNULL_BEGIN
+RTC_EXPORT
@interface RTCSessionDescription : NSObject
/** The type of session description. */