Mark public ObjC APIs as explicitly visible.

webrtc/api/objc/RTCEAGLVideoView.h

 /*
  *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #import <Foundation/Foundation.h>
 #import <UIKit/UIKit.h>
 
 #import "webrtc/api/objc/RTCVideoRenderer.h"
+#import "webrtc/base/objc/RTCMacros.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
 @class RTCEAGLVideoView;
+RTC_EXPORT
 @protocol RTCEAGLVideoViewDelegate
 
 - (void)videoView:(RTCEAGLVideoView *)videoView didChangeVideoSize:(CGSize)size;
 
 @end
 
 /**
  * RTCEAGLVideoView is an RTCVideoRenderer which renders video frames in its
  * bounds using OpenGLES 2.0.
  */
+RTC_EXPORT
 @interface RTCEAGLVideoView : UIView <RTCVideoRenderer>
 
 @property(nonatomic, weak) id<RTCEAGLVideoViewDelegate> delegate;
 
 @end
 
 NS_ASSUME_NONNULL_END