[Sync] Support commit only types.

components/sync/engine_impl/cycle/nudge_tracker.cc

Index: components/sync/engine_impl/cycle/nudge_tracker.cc
diff --git a/components/sync/engine_impl/cycle/nudge_tracker.cc b/components/sync/engine_impl/cycle/nudge_tracker.cc
index 15e83e1c6b8edf0f054112a0c7b500c1fbd3e0aa..365b73c18833314bfd1c337dcd1613c305664b0f 100644
--- a/components/sync/engine_impl/cycle/nudge_tracker.cc
+++ b/components/sync/engine_impl/cycle/nudge_tracker.cc
@@ -24,6 +24,7 @@ base::TimeDelta GetDefaultDelayForType(ModelType model_type,
                                        base::TimeDelta minimum_delay) {
   switch (model_type) {
     case AUTOFILL:
+    case USER_EVENTS:
       // Accompany types rely on nudges from other types, and hence have long
       // nudge delays.
       return base::TimeDelta::FromSeconds(kDefaultShortPollIntervalSeconds);