Fix resolveSubsequentPeriod in EPII.

getNextPeriod might return C.INDEX_UNSET.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=159676949

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

@@ -1083,6 +1083,10 @@ import java.io.IOException;
     int maxIterations = oldTimeline.getPeriodCount();
     int maxIterations = oldTimeline.getPeriodCount();
     for (int i = 0; i < maxIterations && newPeriodIndex == C.INDEX_UNSET; i++) {
     for (int i = 0; i < maxIterations && newPeriodIndex == C.INDEX_UNSET; i++) {
       oldPeriodIndex = oldTimeline.getNextPeriodIndex(oldPeriodIndex, period, window, repeatMode);
       oldPeriodIndex = oldTimeline.getNextPeriodIndex(oldPeriodIndex, period, window, repeatMode);
+      if (oldPeriodIndex == C.INDEX_UNSET) {
+        // We've reached the end of the old timeline.
+        break;
+      }
       newPeriodIndex = newTimeline.getIndexOfPeriod(
       newPeriodIndex = newTimeline.getIndexOfPeriod(
           oldTimeline.getPeriod(oldPeriodIndex, period, true).uid);
           oldTimeline.getPeriod(oldPeriodIndex, period, true).uid);
     }
     }