Add MediaSource.{add,remove}DrmEventListener

Pre-work for issue:#6765

PiperOrigin-RevId: 299322086

library/core/src/main/java/com/google/android/exoplayer2/source/BaseMediaSource.java

@@ -19,6 +19,7 @@ import android.os.Handler;
 import android.os.Looper;
 import android.os.Looper;
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Assertions;
 import java.util.ArrayList;
 import java.util.ArrayList;
@@ -141,6 +142,16 @@ public abstract class BaseMediaSource implements MediaSource {
   }
   }
 
 
   @Override
   @Override
+  public final void addDrmEventListener(Handler handler, DrmSessionEventListener eventListener) {
+    eventDispatcher.addEventListener(handler, eventListener);
+  }
+
+  @Override
+  public final void removeDrmEventListener(DrmSessionEventListener eventListener) {
+    eventDispatcher.removeEventListener(eventListener);
+  }
+
+  @Override
   public final void prepareSource(
   public final void prepareSource(
       MediaSourceCaller caller, @Nullable TransferListener mediaTransferListener) {
       MediaSourceCaller caller, @Nullable TransferListener mediaTransferListener) {
     Looper looper = Looper.myLooper();
     Looper looper = Looper.myLooper();

library/core/src/main/java/com/google/android/exoplayer2/source/MediaSource.java

@@ -19,6 +19,7 @@ import android.os.Handler;
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import java.io.IOException;
 import java.io.IOException;
@@ -229,6 +230,23 @@ public interface MediaSource {
   void removeEventListener(MediaSourceEventListener eventListener);
   void removeEventListener(MediaSourceEventListener eventListener);
 
 
   /**
   /**
+   * Adds a {@link DrmSessionEventListener} to the list of listeners which are notified of DRM
+   * events for this media source.
+   *
+   * @param handler A handler on the which listener events will be posted.
+   * @param eventListener The listener to be added.
+   */
+  void addDrmEventListener(Handler handler, DrmSessionEventListener eventListener);
+
+  /**
+   * Removes a {@link DrmSessionEventListener} from the list of listeners which are notified of DRM
+   * events for this media source.
+   *
+   * @param eventListener The listener to be removed.
+   */
+  void removeDrmEventListener(DrmSessionEventListener eventListener);
+
+  /**
    * Returns the initial dummy timeline that is returned immediately when the real timeline is not
    * Returns the initial dummy timeline that is returned immediately when the real timeline is not
    * yet known, or null to let the player create an initial timeline.
    * yet known, or null to let the player create an initial timeline.
    *
    *