[Sync] Move ModelType and related classes to 'syncer' namespace

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 ce14c1db0c52259c0e2de01f72fbfded3adfb1e3..5c9c7aef54f7d60de51a260f16034cb4f011f460 100644
--- a/sync/internal_api/public/engine/model_safe_worker.h
+++ b/sync/internal_api/public/engine/model_safe_worker.h
@@ -64,10 +64,10 @@ class ModelSafeWorker : public base::RefCountedThreadSafe<ModelSafeWorker> {
   friend class base::RefCountedThreadSafe<ModelSafeWorker>;
 };
 
-// A map that details which ModelSafeGroup each syncable::ModelType
+// A map that details which ModelSafeGroup each syncer::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<syncable::ModelType, ModelSafeGroup>
+typedef std::map<syncer::ModelType, ModelSafeGroup>
     ModelSafeRoutingInfo;
 
 // Caller takes ownership of return value.
@@ -79,14 +79,14 @@ std::string ModelSafeRoutingInfoToString(
 
 // Make a ModelTypePayloadMap for all the enabled types in a
 // ModelSafeRoutingInfo using a default payload.
-syncable::ModelTypePayloadMap ModelSafeRoutingInfoToPayloadMap(
+syncer::ModelTypePayloadMap ModelSafeRoutingInfoToPayloadMap(
     const ModelSafeRoutingInfo& routes,
     const std::string& payload);
 
-syncable::ModelTypeSet GetRoutingInfoTypes(
+syncer::ModelTypeSet GetRoutingInfoTypes(
     const ModelSafeRoutingInfo& routing_info);
 
-ModelSafeGroup GetGroupForModelType(const syncable::ModelType type,
+ModelSafeGroup GetGroupForModelType(const syncer::ModelType type,
                                     const ModelSafeRoutingInfo& routes);
 
 }  // namespace syncer