Added audioSessionDidActivate and audioSessionDidDectivate

webrtc/modules/audio_device/ios/objc/RTCAudioSession.h

 /*
  *  Copyright 2016 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.
  */
 
@@ skipping 58 matching lines @@
  */
 - (void)audioSessionDidStartPlayOrRecord:(RTCAudioSession *)session;
 
 /** Called on a WebRTC thread when the audio device is notified to stop
  *  playback or recording.
  */
 - (void)audioSessionDidStopPlayOrRecord:(RTCAudioSession *)session;
 
 @end
 
+/** This is a protocol used to inform RTCAudioSession when the audio session
+ *  activation state has changed outside of RTCAudioSession. The current known use
+ *  case of this is when CallKit activates the audio session for the application
+ */
+RTC_EXPORT
+@protocol RTCAudioSessionActivationDelegate <NSObject>
+
+/** Called when the audio session is activated outside of the app by iOS. */
+- (void)audioSessionDidActivate:(AVAudioSession *)session;
+
+/** Called when the audio session is deactivated outside of the app by iOS. */
+- (void)audioSessionDidDeactivate:(AVAudioSession *)session;
+
+@end
+
 /** Proxy class for AVAudioSession that adds a locking mechanism similar to
  *  AVCaptureDevice. This is used to that interleaving configurations between
  *  WebRTC and the application layer are avoided.
  *
  *  RTCAudioSession also coordinates activation so that the audio session is
  *  activated only once. See |setActive:error:|.
  */
 RTC_EXPORT
-@interface RTCAudioSession : NSObject
+@interface RTCAudioSession : NSObject <RTCAudioSessionActivationDelegate>
 
 /** Convenience property to access the AVAudioSession singleton. Callers should
  *  not call setters on AVAudioSession directly, but other method invocations
  *  are fine.
  */
 @property(nonatomic, readonly) AVAudioSession *session;
 
 /** Our best guess at whether the session is active based on results of calls to
  *  AVAudioSession.
  */
@@ skipping 94 matching lines @@
 - (BOOL)setPreferredOutputNumberOfChannels:(NSInteger)count
                                      error:(NSError **)outError;
 - (BOOL)overrideOutputAudioPort:(AVAudioSessionPortOverride)portOverride
                           error:(NSError **)outError;
 - (BOOL)setPreferredInput:(AVAudioSessionPortDescription *)inPort
                     error:(NSError **)outError;
 - (BOOL)setInputDataSource:(AVAudioSessionDataSourceDescription *)dataSource
                      error:(NSError **)outError;
 - (BOOL)setOutputDataSource:(AVAudioSessionDataSourceDescription *)dataSource
                       error:(NSError **)outError;
-
 @end
 
 @interface RTCAudioSession (Configuration)
 
 /** Applies the configuration to the current session. Attempts to set all
  *  properties even if previous ones fail. Only the last error will be
  *  returned.
  *  |lockForConfiguration| must be called first.
  */
 - (BOOL)setConfiguration:(RTCAudioSessionConfiguration *)configuration
                    error:(NSError **)outError;
 
 /** Convenience method that calls both setConfiguration and setActive.
  *  |lockForConfiguration| must be called first.
  */
 - (BOOL)setConfiguration:(RTCAudioSessionConfiguration *)configuration
                   active:(BOOL)active
                    error:(NSError **)outError;
 
 @end
 
 NS_ASSUME_NONNULL_END