ChangeReverted.Event: Extend AbstractChangeEvent

Change-Id: I1c17f2ba62d4e0d179792715933d1ddd620465f0
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/extensions/events/ChangeReverted.java b/gerrit-server/src/main/java/com/google/gerrit/server/extensions/events/ChangeReverted.java
index 83bf97f..efadb53 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/extensions/events/ChangeReverted.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/extensions/events/ChangeReverted.java
@@ -63,21 +63,16 @@
     }
   }
 
-  private static class Event implements ChangeRevertedListener.Event {
-    private final ChangeInfo change;
+  private static class Event extends AbstractChangeEvent
+      implements ChangeRevertedListener.Event {
     private final ChangeInfo revertChange;
 
     Event(ChangeInfo change, ChangeInfo revertChange) {
-      this.change = change;
+      super(change);
       this.revertChange = revertChange;
     }
 
     @Override
-    public ChangeInfo getChange() {
-      return change;
-    }
-
-    @Override
     public ChangeInfo getRevertChange() {
       return revertChange;
     }