Add logging around audio session interruptions

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

Index: webrtc/modules/audio_device/ios/objc/RTCAudioSession.mm
diff --git a/webrtc/modules/audio_device/ios/objc/RTCAudioSession.mm b/webrtc/modules/audio_device/ios/objc/RTCAudioSession.mm
index 4d9b9774408a52d80da7df2b054651418eec53bc..694fd045eb02d9f0181877c2dfb97677f6e2d5ec 100644
--- a/webrtc/modules/audio_device/ios/objc/RTCAudioSession.mm
+++ b/webrtc/modules/audio_device/ios/objc/RTCAudioSession.mm
@@ -86,12 +86,14 @@ NSInteger const kRTCAudioSessionErrorConfiguration = -2;
                selector:@selector(handleApplicationDidBecomeActive:)
                    name:UIApplicationDidBecomeActiveNotification
                  object:nil];
+    RTCLog(@"RTCAudioSession init: (%p)", self);

[tkchin_webrtc, 2017/03/29 20:02:51]

nit: "RTCAudioSession (%p): init"
(usually ptr value is shown first)

[Chuck, 2017/03/29 20:29:18]

Done.

   }
   return self;
 }
 
 - (void)dealloc {
   [[NSNotificationCenter defaultCenter] removeObserver:self];
+  RTCLog(@"RTCAudioSession dealloc: (%p)", self);
 }
 
 - (NSString *)description {
@@ -167,6 +169,7 @@ NSInteger const kRTCAudioSessionErrorConfiguration = -2;
 
 // TODO(tkchin): Check for duplicates.
 - (void)addDelegate:(id<RTCAudioSessionDelegate>)delegate {
+  RTCLog(@"Adding delegate: (%p)", delegate);
   if (!delegate) {
     return;
   }
@@ -177,6 +180,7 @@ NSInteger const kRTCAudioSessionErrorConfiguration = -2;
 }
 
 - (void)removeDelegate:(id<RTCAudioSessionDelegate>)delegate {
+  RTCLog(@"Removing delegate: (%p)", delegate);
   if (!delegate) {
     return;
   }
@@ -545,8 +549,9 @@ NSInteger const kRTCAudioSessionErrorConfiguration = -2;
     RTCLog(@"Application became active after an interruption. Treating as interruption end.");
     self.isInterrupted = NO;
     [self updateAudioSessionAfterEvent];
-    [self notifyDidEndInterruptionWithShouldResumeSession:YES];
   }
+  // Always treat application becoming active as an interruption end event.
+  [self notifyDidEndInterruptionWithShouldResumeSession:YES];

[tkchin_webrtc, 2017/03/29 20:02:51]

Hm. I don't recall the details here - but can you check that the audio device
doesn't freak out (ie doesn't try to reinit itself during a call) if we do this
each time app comes to foreground?

Also, can we add a way to distinguish between interruption ends that occur as a
result of app foregrounding, as opposed to when we're notified by OS? Right now
this one appears to be silent.

[Chuck, 2017/03/29 20:29:18]

Modified the logging here so it always logs something.

It looks like this handles multiple end interrupts calls well. It checks the
state of the audio unit and only starts it if needed.

 }
 
 #pragma mark - Private