Display EMSG metadata events in EventLogger

Issue #2176

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=144998826

demo/src/main/java/com/google/android/exoplayer2/demo/EventLogger.java

@@ -29,6 +29,7 @@ import com.google.android.exoplayer2.decoder.DecoderCounters;
 import com.google.android.exoplayer2.drm.DefaultDrmSessionManager;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataRenderer;
+import com.google.android.exoplayer2.metadata.emsg.EventMessage;
 import com.google.android.exoplayer2.metadata.id3.ApicFrame;
 import com.google.android.exoplayer2.metadata.id3.CommentFrame;
 import com.google.android.exoplayer2.metadata.id3.GeobFrame;
@@ -384,6 +385,10 @@ import java.util.Locale;
       } else if (entry instanceof Id3Frame) {
         Id3Frame id3Frame = (Id3Frame) entry;
         Log.d(TAG, prefix + String.format("%s", id3Frame.id));
+      } else if (entry instanceof EventMessage) {
+        EventMessage eventMessage = (EventMessage) entry;
+        Log.d(TAG, prefix + String.format("EMSG: scheme=%s, id=%d, value=%s",
+            eventMessage.schemeIdUri, eventMessage.id, eventMessage.value));
       }
     }
   }