[Sync] Move events files around a bit.

components/sync/engine/events/protocol_event_observer.cc

Index: components/sync/engine/events/protocol_event_observer.cc
diff --git a/components/sync/driver/protocol_event_observer.cc b/components/sync/engine/events/protocol_event_observer.cc
similarity index 82%
rename from components/sync/driver/protocol_event_observer.cc
rename to components/sync/engine/events/protocol_event_observer.cc
index df94635ab7139454939abec6c3d9ec01e9facd03..083abfca4201757fb0175973a4954c72605cb60e 100644
--- a/components/sync/driver/protocol_event_observer.cc
+++ b/components/sync/engine/events/protocol_event_observer.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "components/sync/driver/protocol_event_observer.h"
+#include "components/sync/engine/events/protocol_event_observer.h"
 
 namespace syncer {