sync: Add interfaces for per-type sync

sync/sessions/model_type_registry.h

 // Copyright 2014 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 SYNC_ENGINE_MODEL_TYPE_REGISTRY_H_
 #define SYNC_ENGINE_MODEL_TYPE_REGISTRY_H_
 
 #include <map>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/stl_util.h"
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/engine/model_safe_worker.h"
 
 namespace syncer {
 
 namespace syncable {
 class Directory;
 }  // namespace syncable
 
-class SyncDirectoryUpdateHandler;
-class SyncDirectoryCommitContributor;
+class UpdateHandler;
+class CommitContributor;
 
-typedef std::map<ModelType, SyncDirectoryUpdateHandler*> UpdateHandlerMap;
-typedef std::map<ModelType, SyncDirectoryCommitContributor*>
-    CommitContributorMap;
+typedef std::map<ModelType, UpdateHandler*> UpdateHandlerMap;
+typedef std::map<ModelType, CommitContributor*> CommitContributorMap;
 
 // Keeps track of the sets of active update handlers and commit contributors.
 class SYNC_EXPORT_PRIVATE ModelTypeRegistry {
  public:
   ModelTypeRegistry(
       const std::vector<scoped_refptr<ModelSafeWorker> >& workers,
       syncable::Directory* directory);
   ~ModelTypeRegistry();
 
   // Sets the set of enabled types.
@@ skipping 20 matching lines @@
   // The directory.  Not owned.
   syncable::Directory* directory_;
 
   DISALLOW_COPY_AND_ASSIGN(ModelTypeRegistry);
 };
 
 }  // namespace syncer
 
 #endif // SYNC_ENGINE_MODEL_TYPE_REGISTRY_H_