Re-added call to schedule manifest refreshes.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127951757

library/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java

@@ -159,6 +159,7 @@ public final class DashMediaSource implements MediaSource {
       for (int i = 0; i < periods.length; i++) {
         periods[i].updateManifest(manifest, i);
       }
+      scheduleManifestRefresh();
     }
   }