Populate versions on individual nodes in sync model and native bookmark model.

sync/internal_api/public/base_transaction.h

 // Copyright (c) 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 SYNC_INTERNAL_API_PUBLIC_BASE_TRANSACTION_H_
 #define SYNC_INTERNAL_API_PUBLIC_BASE_TRANSACTION_H_
 
 #include "sync/internal_api/public/user_share.h"
 
 #include "sync/internal_api/public/base/model_type.h"
@@ skipping 17 matching lines @@
  public:
   // Provide access to the underlying syncable objects from BaseNode.
   virtual syncable::BaseTransaction* GetWrappedTrans() const = 0;
   Cryptographer* GetCryptographer() const;
   ModelTypeSet GetEncryptedTypes() const;
 
   syncable::Directory* GetDirectory() const {
     return directory_;
   }
 
+  // Return |transaction_version| of |type| stored in sync directory's
+  // persisted info.
+  int64 GetModelVersion(ModelType type);
+
  protected:
   explicit BaseTransaction(UserShare* share);
   virtual ~BaseTransaction();
 
   BaseTransaction() : directory_(NULL) { }
 
  private:
   syncable::Directory* directory_;
 
   DISALLOW_COPY_AND_ASSIGN(BaseTransaction);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_BASE_TRANSACTION_H_