[Sync] Sanity test for UserEvents.

components/sync/test/fake_server/unique_client_entity.h

Index: components/sync/test/fake_server/unique_client_entity.h
diff --git a/components/sync/test/fake_server/unique_client_entity.h b/components/sync/test/fake_server/unique_client_entity.h
index 5fe819dcd48ebf7c5cde6d88b33b31ce22ec83d5..c9c424539c1bb0b55136acb94383a0574c4d46e8 100644
--- a/components/sync/test/fake_server/unique_client_entity.h
+++ b/components/sync/test/fake_server/unique_client_entity.h
@@ -48,10 +48,6 @@ class UniqueClientEntity : public FakeServerEntity {
       const std::string& name,
       const sync_pb::EntitySpecifics& entity_specifics);
 
-  // Derives an ID from a unique client tagged entity.
-  static std::string EffectiveIdForClientTaggedEntity(
-      const sync_pb::SyncEntity& entity);
-
   // FakeServerEntity implementation.
   bool RequiresParentId() const override;
   std::string GetParentId() const override;