iOS audio session isInterrupted flag does not get reset correctly:

webrtc/modules/audio_device/ios/audio_device_ios.mm

 /*
  *  Copyright (c) 2012 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 779 matching lines @@
   LOGI() << "InitPlayOrRecord";
 
   // There should be no audio unit at this point.
   if (!CreateAudioUnit()) {
     return false;
   }
 
   RTCAudioSession* session = [RTCAudioSession sharedInstance];
   // Subscribe to audio session events.
   [session pushDelegate:audio_session_observer_];
+  is_interrupted_ = session.isInterrupted ? true : false;
 
   // Lock the session to make configuration changes.
   [session lockForConfiguration];
   NSError* error = nil;
   if (![session beginWebRTCSession:&error]) {
     [session unlockForConfiguration];
     RTCLogError(@"Failed to begin WebRTC session: %@",
                 error.localizedDescription);
     return false;
   }
@@ skipping 26 matching lines @@
 
   // All I/O should be stopped or paused prior to deactivating the audio
   // session, hence we deactivate as last action.
   [session lockForConfiguration];
   UnconfigureAudioSession();
   [session endWebRTCSession:nil];
   [session unlockForConfiguration];
 }
 
 }  // namespace webrtc