[Sync] Remove some unnecessary typedefs in SyncBackendRegistrar.

components/sync/driver/glue/sync_backend_registrar.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_REGISTRAR_H_
 #define COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_REGISTRAR_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 98 matching lines @@
   void OnChangesApplied(ModelType model_type,
                         int64_t model_version,
                         const BaseTransaction* trans,
                         const ImmutableChangeRecordList& changes) override;
   void OnChangesComplete(ModelType model_type) override;
 
   void GetWorkers(std::vector<scoped_refptr<ModelSafeWorker>>* out);
   void GetModelSafeRoutingInfo(ModelSafeRoutingInfo* out);
 
  private:
-  typedef std::map<ModelSafeGroup, scoped_refptr<ModelSafeWorker>> WorkerMap;
-  typedef std::map<ModelType, ChangeProcessor*> ProcessorMap;
-
   // Add a worker for |group| to the worker map if one is successfully created
   // by |worker_factory|.
   void MaybeAddWorker(ModelSafeWorkerFactory worker_factory,
                       ModelSafeGroup group);
 
   // Returns the change processor for the given model, or null if none
   // exists.  Must be called from |group|'s native thread.
   ChangeProcessor* GetProcessor(ModelType type) const;
 
   // Must be called with |lock_| held.  Simply returns the change
@@ skipping 13 matching lines @@
   // Name used for debugging.
   const std::string name_;
 
   // Checker for the UI thread (where this object is constructed).
   base::ThreadChecker ui_thread_checker_;
 
   // Protects all variables below.
   mutable base::Lock lock_;
 
   // Workers created by this SyncBackendRegistrar.
-  WorkerMap workers_;
-
-  ModelSafeRoutingInfo routing_info_;
+  std::map<ModelSafeGroup, scoped_refptr<ModelSafeWorker>> workers_;
 
   // The change processors that handle the different data types.
-  ProcessorMap processors_;
+  std::map<ModelType, ChangeProcessor*> processors_;
+
+  // Maps ModelType to ModelSafeGroup.
+  ModelSafeRoutingInfo routing_info_;
 
   // The types that were enabled as of the last configuration. Updated on each
   // call to ConfigureDataTypes as well as SetInitialTypes.
   ModelTypeSet last_configured_types_;
 
   // Set of types with non-blocking implementation (as opposed to directory
   // based).
   ModelTypeSet non_blocking_types_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendRegistrar);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_REGISTRAR_H_