Mark public ObjC APIs as explicitly visible.

webrtc/base/objc/RTCFileLogger.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 "webrtc/base/objc/RTCMacros.h"
+
 typedef NS_ENUM(NSUInteger, RTCFileLoggerSeverity) {
   RTCFileLoggerSeverityVerbose,
   RTCFileLoggerSeverityInfo,
   RTCFileLoggerSeverityWarning,
   RTCFileLoggerSeverityError
 };
 
 typedef NS_ENUM(NSUInteger, RTCFileLoggerRotationType) {
   RTCFileLoggerTypeCall,
   RTCFileLoggerTypeApp,
 };
 
 NS_ASSUME_NONNULL_BEGIN
 
 // This class intercepts WebRTC logs and saves them to a file. The file size
 // will not exceed the given maximum bytesize. When the maximum bytesize is
 // reached, logs are rotated according to the rotationType specified.
 // For kRTCFileLoggerTypeCall, logs from the beginning and the end
 // are preserved while the middle section is overwritten instead.
 // For kRTCFileLoggerTypeApp, the oldest log is overwritten.
 // This class is not threadsafe.
+RTC_EXPORT
 @interface RTCFileLogger : NSObject
 
 // The severity level to capture. The default is kRTCFileLoggerSeverityInfo.
 @property(nonatomic, assign) RTCFileLoggerSeverity severity;
 
 // The rotation type for this file logger. The default is
 // kRTCFileLoggerTypeCall.
 @property(nonatomic, readonly) RTCFileLoggerRotationType rotationType;
 
 // Disables buffering disk writes. Should be set before |start|. Buffering
@@ skipping 21 matching lines @@
 - (void)stop;
 
 // Returns the current contents of the logs, or nil if start has been called
 // without a stop.
 - (NSData *)logData;
 
 @end
 
 NS_ASSUME_NONNULL_END