Refactor ModelTypePayloadMap and ObjectIdPayloadMap to StateMaps.

sync/internal_api/public/engine/model_safe_worker.cc

Index: sync/internal_api/public/engine/model_safe_worker.cc
diff --git a/sync/internal_api/public/engine/model_safe_worker.cc b/sync/internal_api/public/engine/model_safe_worker.cc
index cd7eaea9b56fd53c128a2885a78b3ca48ed7f58c..2212a4176d140565f0aeca00ebe0c0e8785233e7 100644
--- a/sync/internal_api/public/engine/model_safe_worker.cc
+++ b/sync/internal_api/public/engine/model_safe_worker.cc
@@ -29,15 +29,15 @@ std::string ModelSafeRoutingInfoToString(
   return json;
 }
 
-ModelTypePayloadMap ModelSafeRoutingInfoToPayloadMap(
+ModelTypeStateMap ModelSafeRoutingInfoToStateMap(
     const ModelSafeRoutingInfo& routes,
     const std::string& payload) {
-  ModelTypePayloadMap types_with_payloads;
+  ModelTypeStateMap type_state_map;
   for (ModelSafeRoutingInfo::const_iterator i = routes.begin();
        i != routes.end(); ++i) {
-    types_with_payloads[i->first] = payload;
+    type_state_map[i->first].payload = payload;
   }
-  return types_with_payloads;
+  return type_state_map;
 }
 
 ModelTypeSet GetRoutingInfoTypes(const ModelSafeRoutingInfo& routing_info) {