Listen to the audio focus event for MSE/EME

media/base/android/media_source_player.cc

Index: media/base/android/media_source_player.cc
diff --git a/media/base/android/media_source_player.cc b/media/base/android/media_source_player.cc
index 830defae1946145be6163e69e1f4eb59d3939bde..8306ad969b1a5eed27c7ba584c2db7322ad98260 100644
--- a/media/base/android/media_source_player.cc
+++ b/media/base/android/media_source_player.cc
@@ -194,6 +194,7 @@ void MediaSourcePlayer::Release() {
   playing_ = false;
 
   decoder_starvation_callback_.Cancel();
+  DetachListener();
 }
 
 void MediaSourcePlayer::SetVolume(double volume) {
@@ -226,6 +227,7 @@ void MediaSourcePlayer::StartInternal() {
   // be clear (not encrypted) or encrypted with different keys. So
   // |is_waiting_for_key_| condition may not be true anymore.
   is_waiting_for_key_ = false;
+  AttachListener(NULL);
 
   SetPendingEvent(PREFETCH_REQUEST_EVENT_PENDING);
   ProcessPendingEvents();