Attach the IDs of expired messages to MessageExpiredEvent.

briar-api/src/net/sf/briar/api/db/event/MessageExpiredEvent.java

@@ -1,9 +1,22 @@
 package net.sf.briar.api.db.event;
 
+import java.util.Collection;
+
+import net.sf.briar.api.messaging.MessageId;
+
 /**
  * An event that is broadcast when one or messages expire from the database,
  * potentially changing the database's retention time.
  */
 public class MessageExpiredEvent extends DatabaseEvent {
 
+	private final Collection<MessageId> expired;
+
+	public MessageExpiredEvent(Collection<MessageId> expired) {
+		this.expired = expired;
+	}
+
+	public Collection<MessageId> getMessageIds() {
+		return expired;
+	}
 }