Migrate usages of PositionInfo#windowIndex to mediaItemIndex

PiperOrigin-RevId: 403376452

extensions/cast/src/main/java/com/google/android/exoplayer2/ext/cast/CastPlayer.java

@@ -463,7 +463,7 @@ public final class CastPlayer extends BasePlayer {
             listener.onPositionDiscontinuity(DISCONTINUITY_REASON_SEEK);
             listener.onPositionDiscontinuity(oldPosition, newPosition, DISCONTINUITY_REASON_SEEK);
           });
-      if (oldPosition.windowIndex != newPosition.windowIndex) {
+      if (oldPosition.mediaItemIndex != newPosition.mediaItemIndex) {
         // TODO(internal b/182261884): queue `onMediaItemTransition` event when the media item is
         // repeated.
         MediaItem mediaItem = getCurrentTimeline().getWindow(windowIndex, window).mediaItem;

library/core/src/main/java/com/google/android/exoplayer2/util/EventLogger.java

@@ -151,8 +151,8 @@ public class EventLogger implements AnalyticsListener {
         .append("reason=")
         .append(getDiscontinuityReasonString(reason))
         .append(", PositionInfo:old [")
-        .append("window=")
-        .append(oldPosition.windowIndex)
+        .append("mediaItem=")
+        .append(oldPosition.mediaItemIndex)
         .append(", period=")
         .append(oldPosition.periodIndex)
         .append(", pos=")
@@ -168,8 +168,8 @@ public class EventLogger implements AnalyticsListener {
     }
     builder
         .append("], PositionInfo:new [")
-        .append("window=")
-        .append(newPosition.windowIndex)
+        .append("mediaItem=")
+        .append(newPosition.mediaItemIndex)
         .append(", period=")
         .append(newPosition.periodIndex)
         .append(", pos=")