remove module-wide warning suppression.

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

 /*
  *  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 175 matching lines @@
   }
   @synchronized(self) {
     _delegates.erase(std::remove(_delegates.begin(),
                                  _delegates.end(),
                                  delegate),
                      _delegates.end());
     [self removeZeroedDelegates];
   }
 }
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wthread-safety-analysis"
+
 - (void)lockForConfiguration {
   _crit.Enter();
   rtc::AtomicOps::Increment(&_lockRecursionCount);
 }
 
 - (void)unlockForConfiguration {
   // Don't let threads other than the one that called lockForConfiguration
   // unlock.
   if (_crit.TryEnter()) {
     rtc::AtomicOps::Decrement(&_lockRecursionCount);
     // One unlock for the tryLock, and another one to actually unlock. If this
     // was called without anyone calling lock, we will hit an assertion.
     _crit.Leave();
     _crit.Leave();
   }
 }
 
+#pragma clang diagnostic pop
+
 #pragma mark - AVAudioSession proxy methods
 
 - (NSString *)category {
   return self.session.category;
 }
 
 - (AVAudioSessionCategoryOptions)categoryOptions {
   return self.session.categoryOptions;
 }
 
@@ skipping 630 matching lines @@
 - (void)notifyDidStopPlayOrRecord {
   for (auto delegate : self.delegates) {
     SEL sel = @selector(audioSessionDidStopPlayOrRecord:);
     if ([delegate respondsToSelector:sel]) {
       [delegate audioSessionDidStopPlayOrRecord:self];
     }
   }
 }
 
 @end