Revert 142862 - Change the way we are stopping audio stream on Mac once again.

media/audio/mac/audio_output_mac.cc

Index: media/audio/mac/audio_output_mac.cc
===================================================================
--- media/audio/mac/audio_output_mac.cc	(revision 142884)
+++ media/audio/mac/audio_output_mac.cc	(working copy)
@@ -60,7 +60,7 @@
       should_swizzle_(false),
       should_down_mix_(false),
       stopped_event_(true /* manual reset */, false /* initial state */),
-      stop_requested_(false) {
+      num_buffers_left_(kNumBuffers) {
   // We must have a manager.
   DCHECK(manager_);
   // A frame is one sample across all channels. In interleaved audio the per
@@ -379,37 +379,6 @@
   return false;
 }
 
-void PCMQueueOutAudioOutputStream::IsRunningCallback(
-    void* p_this,
-    AudioQueueRef queue,
-    AudioQueuePropertyID inID) {
-  PCMQueueOutAudioOutputStream* audio_stream =
-      static_cast<PCMQueueOutAudioOutputStream*>(p_this);
-  UInt32 running = 0;
-  UInt32 size = sizeof(running);
-  OSStatus err = AudioQueueGetProperty(queue,
-                                       kAudioQueueProperty_IsRunning,
-                                       &running,
-                                       &size);
-  if (err) {
-    audio_stream->HandleError(err);
-    return;
-  }
-  if (!running) {
-    // Remove property listener, we don't need it anymore.
-    OSStatus err = AudioQueueRemovePropertyListener(
-        queue,
-        kAudioQueueProperty_IsRunning,
-        PCMQueueOutAudioOutputStream::IsRunningCallback,
-        audio_stream);
-    if (err != noErr)
-      audio_stream->HandleError(err);
-
-    // Ok, finally signal that stream is not running.
-    audio_stream->stopped_event_.Signal();
-  }
-}
-
 // Note to future hackers of this function: Do not add locks to this function
 // that are held through any calls made back into AudioQueue APIs, or other
 // OS audio functions.  This is because the OS dispatch may grab external
@@ -427,28 +396,25 @@
   AudioSourceCallback* source = audio_stream->GetSource();
   if (!source) {
     // PCMQueueOutAudioOutputStream::Stop() is waiting for callback to
-    // stop the stream and signal when all activity ceased (we probably
-    // can stop the stream there, but it is better to have all the
-    // complex logic in one place; stopping latency is not very important
-    // if you reuse audio stream in the mixer and not close it immediately).
-    if (!audio_stream->stop_requested_) {
-      audio_stream->stop_requested_ = true;
-      // Before actually stopping the stream, register callback that
-      // OS would call when status of "is running" property changes.
-      // This way we (hopefully) would know when stream is actually
-      // stopped and it is safe to dispose it.
-      OSStatus err = AudioQueueAddPropertyListener(
-          queue,
-          kAudioQueueProperty_IsRunning,
-          PCMQueueOutAudioOutputStream::IsRunningCallback,
-          audio_stream);
+    // stop the stream and signal when all callbacks are done.
+    // (we probably can stop the stream there, but it is better to have
+    // all the complex logic in one place; stopping latency is not very
+    // important if you reuse audio stream in the mixer and not close it
+    // immediately).
+    --audio_stream->num_buffers_left_;
+    if (audio_stream->num_buffers_left_ == kNumBuffers - 1) {
+      // First buffer after stop requested, stop the queue.
+      OSStatus err = AudioQueueStop(audio_stream->audio_queue_, true);
       if (err != noErr)
         audio_stream->HandleError(err);
-      // Now stop the queue.
-      err = AudioQueueStop(queue, true);
-      if (err != noErr)
-        audio_stream->HandleError(err);
     }
+    if (audio_stream->num_buffers_left_ == 0) {
+      // Now we finally saw all the buffers.
+      // Signal that stopping is complete.
+      // Should never touch audio_stream after signaling as it
+      // can be deleted at any moment.
+      audio_stream->stopped_event_.Signal();
+    }
     return;
   }
 
@@ -543,7 +509,7 @@
   SetSource(callback);
   pending_bytes_ = 0;
   stopped_event_.Reset();
-  stop_requested_ = false;
+  num_buffers_left_ = kNumBuffers;
   // Ask the source to pre-fill all our buffers before playing.
   for (uint32 ix = 0; ix != kNumBuffers; ++ix) {
     buffer_[ix]->mAudioDataByteSize = 0;