Treat foreground event as interruption end.

webrtc/modules/audio_device/ios/objc/RTCAudioSession+Private.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 13 matching lines @@
 @property(nonatomic, readonly) int activationCount;
 
 /** The number of times |beginWebRTCSession| was called without a balanced call
  *  to |endWebRTCSession|.
  */
 @property(nonatomic, readonly) int webRTCSessionCount;
 
 /** Convenience BOOL that checks useManualAudio and isAudioEnebled. */
 @property(readonly) BOOL canPlayOrRecord;
 
+/** Tracks whether we have been sent an interruption event that hasn't been matched by either an
+ *  interrupted end event or a foreground event.
+ */
+@property(nonatomic, assign) BOOL isInterrupted;
+
 - (BOOL)checkLock:(NSError **)outError;
 
 /** Adds the delegate to the list of delegates, and places it at the front of
  *  the list. This delegate will be notified before other delegates of
  *  audio events.
  */
 - (void)pushDelegate:(id<RTCAudioSessionDelegate>)delegate;
 
 /** Signals RTCAudioSession that a WebRTC session is about to begin and
  *  audio configuration is needed. Will configure the audio session for WebRTC
@@ skipping 38 matching lines @@
     previousRoute:(AVAudioSessionRouteDescription *)previousRoute;
 - (void)notifyMediaServicesWereLost;
 - (void)notifyMediaServicesWereReset;
 - (void)notifyDidChangeCanPlayOrRecord:(BOOL)canPlayOrRecord;
 - (void)notifyDidStartPlayOrRecord;
 - (void)notifyDidStopPlayOrRecord;
 
 @end
 
 NS_ASSUME_NONNULL_END