Treat foreground event as interruption end.

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

Index: webrtc/modules/audio_device/ios/objc/RTCAudioSession+Private.h
diff --git a/webrtc/modules/audio_device/ios/objc/RTCAudioSession+Private.h b/webrtc/modules/audio_device/ios/objc/RTCAudioSession+Private.h
index cb506c345a9986ea710946de8ec1f6ec82ae1874..36be0143869a99bb7eb2100898701be3c8049077 100644
--- a/webrtc/modules/audio_device/ios/objc/RTCAudioSession+Private.h
+++ b/webrtc/modules/audio_device/ios/objc/RTCAudioSession+Private.h
@@ -31,6 +31,11 @@ NS_ASSUME_NONNULL_BEGIN
 /** 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