[Sync] Remove unneeded 'using syncer::' lines and 'syncer::' scopings

sync/engine/throttled_data_type_tracker.cc

Index: sync/engine/throttled_data_type_tracker.cc
diff --git a/sync/engine/throttled_data_type_tracker.cc b/sync/engine/throttled_data_type_tracker.cc
index 42d1246f37f0c46430177327447ad4c6c92e2526..9cb24612cba7c8eb0e6ef20797e51ce5c1a256ca 100644
--- a/sync/engine/throttled_data_type_tracker.cc
+++ b/sync/engine/throttled_data_type_tracker.cc
@@ -12,16 +12,15 @@ namespace syncer {
 ThrottledDataTypeTracker::ThrottledDataTypeTracker(AllStatus *allstatus)
     : allstatus_(allstatus) {
   if (allstatus_) {
-    allstatus_->SetThrottledTypes(syncer::ModelTypeSet());
+    allstatus_->SetThrottledTypes(ModelTypeSet());
   }
 }
 
 ThrottledDataTypeTracker::~ThrottledDataTypeTracker() { }
 
-void ThrottledDataTypeTracker::SetUnthrottleTime(syncer::ModelTypeSet types,
+void ThrottledDataTypeTracker::SetUnthrottleTime(ModelTypeSet types,
                                                  const base::TimeTicks& time) {
-  for (syncer::ModelTypeSet::Iterator it = types.First();
-       it.Good(); it.Inc()) {
+  for (ModelTypeSet::Iterator it = types.First(); it.Good(); it.Inc()) {
     unthrottle_times_[it.Get()] = time;
   }
 
@@ -60,8 +59,8 @@ void ThrottledDataTypeTracker::PruneUnthrottledTypes(
   }
 }
 
-syncer::ModelTypeSet ThrottledDataTypeTracker::GetThrottledTypes() const {
-  syncer::ModelTypeSet types;
+ModelTypeSet ThrottledDataTypeTracker::GetThrottledTypes() const {
+  ModelTypeSet types;
   for (UnthrottleTimes::const_iterator it = unthrottle_times_.begin();
        it != unthrottle_times_.end(); ++it) {
     types.Put(it->first);