Fix review comments

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/drm/DummyExoMediaDrm.java

@@ -24,7 +24,6 @@ import androidx.media3.common.DrmInitData;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
 import androidx.media3.decoder.CryptoConfig;
-import com.google.common.collect.ImmutableList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -121,17 +120,6 @@ public final class DummyExoMediaDrm implements ExoMediaDrm {
     throw new IllegalStateException();
   }
 
-  @Override
-  public void removeOfflineLicense(byte[] keySetId) {
-    // Should not be invoked. No session should exist.
-    throw new IllegalStateException();
-  }
-
-  @Override
-  public ImmutableList<byte[]> getOfflineLicenseKeySetIds() {
-    return ImmutableList.of();
-  }
-
   @Override
   @Nullable
   public PersistableBundle getMetrics() {

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/drm/ExoMediaDrm.java

@@ -536,18 +536,26 @@ public interface ExoMediaDrm {
    * <p>See {@link MediaDrm#removeOfflineLicense(byte[])} for more details.
    *
    * @param keySetId The {@code keySetId} of the license to remove.
+   * @throws UnsupportedOperationException if the implementation doesn't support this method.
    */
-  void removeOfflineLicense(byte[] keySetId);
+  default void removeOfflineLicense(byte[] keySetId) {
+    throw new UnsupportedOperationException();
+  }
 
   /**
    * Returns a list of the {@code keySetIds} for all offline licenses.
    *
    * <p>This is an optional method, and some implementations may only support it on certain Android
-   * API levels. If the method is unsupported an empty list is returned.
+   * API levels.
    *
    * <p>See {@link MediaDrm#getOfflineLicenseKeySetIds()} for more details.
+   *
+   * @return The list of {@code keySetIds} for all offline licenses.
+   * @throws UnsupportedOperationException if the implementation doesn't support this method.
    */
-  List<byte[]> getOfflineLicenseKeySetIds();
+  default List<byte[]> getOfflineLicenseKeySetIds() {
+    throw new UnsupportedOperationException();
+  }
 
   /**
    * Returns metrics data for this ExoMediaDrm instance, or {@code null} if metrics are unavailable.
@@ -609,6 +617,4 @@ public interface ExoMediaDrm {
    */
   @C.CryptoType
   int getCryptoType();
-
-
 }

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/drm/FrameworkMediaDrm.java

@@ -26,7 +26,6 @@ import android.media.MediaDrmException;
 import android.media.NotProvisionedException;
 import android.media.UnsupportedSchemeException;
 import android.media.metrics.LogSessionId;
-import android.os.Build;
 import android.os.PersistableBundle;
 import android.text.TextUtils;
 import androidx.annotation.DoNotInline;
@@ -44,7 +43,6 @@ import androidx.media3.common.util.Util;
 import androidx.media3.exoplayer.analytics.PlayerId;
 import androidx.media3.extractor.mp4.PsshAtomUtil;
 import com.google.common.base.Charsets;
-import com.google.common.collect.ImmutableList;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.ArrayList;
@@ -330,19 +328,21 @@ public final class FrameworkMediaDrm implements ExoMediaDrm {
   }
 
   @Override
-  @RequiresApi(Build.VERSION_CODES.Q)
+  @UnstableApi
+  @RequiresApi(29)
   public void removeOfflineLicense(byte[] keySetId) {
-    if (Util.SDK_INT < Build.VERSION_CODES.Q) {
+    if (Util.SDK_INT < 29) {
       throw new UnsupportedOperationException();
     }
     mediaDrm.removeOfflineLicense(keySetId);
   }
 
   @Override
-  @RequiresApi(Build.VERSION_CODES.Q)
+  @UnstableApi
+  @RequiresApi(29)
   public List<byte[]> getOfflineLicenseKeySetIds() {
-    if (Util.SDK_INT < Build.VERSION_CODES.Q) {
-      return ImmutableList.of();
+    if (Util.SDK_INT < 29) {
+      throw new UnsupportedOperationException();
     }
     return mediaDrm.getOfflineLicenseKeySetIds();
   }

libraries/test_utils/src/main/java/androidx/media3/test/utils/FakeExoMediaDrm.java

@@ -361,16 +361,6 @@ public final class FakeExoMediaDrm implements ExoMediaDrm {
     throw new UnsupportedOperationException();
   }
 
-  @Override
-  public void removeOfflineLicense(byte[] keySetId) {
-    throw new UnsupportedOperationException();
-  }
-
-  @Override
-  public ImmutableList<byte[]> getOfflineLicenseKeySetIds() {
-    return ImmutableList.of();
-  }
-
   @Nullable
   @Override
   public PersistableBundle getMetrics() {