Remove threading requirement from listener registration methods.

These methods operate on a thread-safe collection and are thus
inherently thread-safe. This simplifies some player setup configurations
where initial listeners are added on a background thread (e.g. when
using a dependency injection framework).

PiperOrigin-RevId: 310113181

library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java

@@ -659,11 +659,13 @@ public class SimpleExoPlayer extends BasePlayer
 
   @Override
   public void addAudioListener(AudioListener listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     audioListeners.add(listener);
   }
 
   @Override
   public void removeAudioListener(AudioListener listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     audioListeners.remove(listener);
   }
 
@@ -807,7 +809,7 @@ public class SimpleExoPlayer extends BasePlayer
    * @param listener The listener to be added.
    */
   public void addAnalyticsListener(AnalyticsListener listener) {
-    verifyApplicationThread();
+    // Don't verify application thread. We allow calls to this method from any thread.
     analyticsCollector.addListener(listener);
   }
 
@@ -817,7 +819,7 @@ public class SimpleExoPlayer extends BasePlayer
    * @param listener The listener to be removed.
    */
   public void removeAnalyticsListener(AnalyticsListener listener) {
-    verifyApplicationThread();
+    // Don't verify application thread. We allow calls to this method from any thread.
     analyticsCollector.removeListener(listener);
   }
 
@@ -906,11 +908,13 @@ public class SimpleExoPlayer extends BasePlayer
 
   @Override
   public void addVideoListener(com.google.android.exoplayer2.video.VideoListener listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     videoListeners.add(listener);
   }
 
   @Override
   public void removeVideoListener(com.google.android.exoplayer2.video.VideoListener listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     videoListeners.remove(listener);
   }
 
@@ -980,11 +984,13 @@ public class SimpleExoPlayer extends BasePlayer
 
   @Override
   public void addTextOutput(TextOutput listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     textOutputs.add(listener);
   }
 
   @Override
   public void removeTextOutput(TextOutput listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     textOutputs.remove(listener);
   }
 
@@ -1021,11 +1027,13 @@ public class SimpleExoPlayer extends BasePlayer
 
   @Override
   public void addMetadataOutput(MetadataOutput listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     metadataOutputs.add(listener);
   }
 
   @Override
   public void removeMetadataOutput(MetadataOutput listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     metadataOutputs.remove(listener);
   }
 
@@ -1130,13 +1138,13 @@ public class SimpleExoPlayer extends BasePlayer
 
   @Override
   public void addListener(Player.EventListener listener) {
-    verifyApplicationThread();
+    // Don't verify application thread. We allow calls to this method from any thread.
     player.addListener(listener);
   }
 
   @Override
   public void removeListener(Player.EventListener listener) {
-    verifyApplicationThread();
+    // Don't verify application thread. We allow calls to this method from any thread.
     player.removeListener(listener);
   }
 
@@ -1691,11 +1699,13 @@ public class SimpleExoPlayer extends BasePlayer
 
   @Override
   public void addDeviceListener(DeviceListener listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     deviceListeners.add(listener);
   }
 
   @Override
   public void removeDeviceListener(DeviceListener listener) {
+    // Don't verify application thread. We allow calls to this method from any thread.
     deviceListeners.remove(listener);
   }