Add shouldDisableBuffering to RTCFileLogger.

talk/app/webrtc/objc/RTCFileLogger.mm

Index: talk/app/webrtc/objc/RTCFileLogger.mm
diff --git a/talk/app/webrtc/objc/RTCFileLogger.mm b/talk/app/webrtc/objc/RTCFileLogger.mm
index 44ada3e22e2a549dfc65bb88c45f0858aed50b0b..c927f76eb63060803915bdac32b6cea84fcb3348 100644
--- a/talk/app/webrtc/objc/RTCFileLogger.mm
+++ b/talk/app/webrtc/objc/RTCFileLogger.mm
@@ -46,6 +46,7 @@ const char *kRTCFileLoggerRotatingLogPrefix = "rotating_log";
 
 @synthesize severity = _severity;
 @synthesize rotationType = _rotationType;
+@synthesize shouldDisableBuffering = _shouldDisableBuffering;
 
 - (instancetype)init {
   NSArray *paths = NSSearchPathForDirectoriesInDomains(
@@ -121,6 +122,9 @@ const char *kRTCFileLoggerRotatingLogPrefix = "rotating_log";
     _logSink.reset();
     return;
   }
+  if (_shouldDisableBuffering) {
+    _logSink->DisableBuffering();
+  }
   rtc::LogMessage::LogThreads(true);
   rtc::LogMessage::LogTimestamps(true);
   rtc::LogMessage::AddLogToStream(_logSink.get(), [self rtcSeverity]);