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

sync/internal_api/public/engine/model_safe_worker.h

Index: sync/internal_api/public/engine/model_safe_worker.h
diff --git a/sync/internal_api/public/engine/model_safe_worker.h b/sync/internal_api/public/engine/model_safe_worker.h
index 193e41d1004e6520c8846cec89dda04ce9426a10..a3a95a50a218c487c42ad4c0da5e810afae6030d 100644
--- a/sync/internal_api/public/engine/model_safe_worker.h
+++ b/sync/internal_api/public/engine/model_safe_worker.h
@@ -63,11 +63,10 @@ class ModelSafeWorker : public base::RefCountedThreadSafe<ModelSafeWorker> {
   friend class base::RefCountedThreadSafe<ModelSafeWorker>;
 };
 
-// A map that details which ModelSafeGroup each syncer::ModelType
+// A map that details which ModelSafeGroup each ModelType
 // belongs to.  Routing info can change in response to the user enabling /
 // disabling sync for certain types, as well as model association completions.
-typedef std::map<syncer::ModelType, ModelSafeGroup>
-    ModelSafeRoutingInfo;
+typedef std::map<ModelType, ModelSafeGroup> ModelSafeRoutingInfo;
 
 // Caller takes ownership of return value.
 base::DictionaryValue* ModelSafeRoutingInfoToValue(
@@ -78,14 +77,13 @@ std::string ModelSafeRoutingInfoToString(
 
 // Make a ModelTypePayloadMap for all the enabled types in a
 // ModelSafeRoutingInfo using a default payload.
-syncer::ModelTypePayloadMap ModelSafeRoutingInfoToPayloadMap(
+ModelTypePayloadMap ModelSafeRoutingInfoToPayloadMap(
     const ModelSafeRoutingInfo& routes,
     const std::string& payload);
 
-syncer::ModelTypeSet GetRoutingInfoTypes(
-    const ModelSafeRoutingInfo& routing_info);
+ModelTypeSet GetRoutingInfoTypes(const ModelSafeRoutingInfo& routing_info);
 
-ModelSafeGroup GetGroupForModelType(const syncer::ModelType type,
+ModelSafeGroup GetGroupForModelType(const ModelType type,
                                     const ModelSafeRoutingInfo& routes);
 
 }  // namespace syncer