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

sync/internal_api/public/write_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_WRITE_TRANSACTION_H_
 #define SYNC_INTERNAL_API_PUBLIC_WRITE_TRANSACTION_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "sync/internal_api/public/base_transaction.h"
@@ skipping 12 matching lines @@
 // Sync API's WriteTransaction is a read/write BaseTransaction.  It wraps
 // a syncable::WriteTransaction.
 //
 // NOTE: Only a single model type can be mutated for a given
 // WriteTransaction.
 class WriteTransaction : public BaseTransaction {
  public:
   // Start a new read/write transaction.
   WriteTransaction(const tracked_objects::Location& from_here,
                    UserShare* share);
+  // |transaction_version| stores updated model and nodes version if model
+  // is changed by the transaction, or syncer::syncable::kInvalidTransaction
+  // if not after transaction is closed. This constructor is used for model
+  // types that support embassy data.
+  WriteTransaction(const tracked_objects::Location& from_here,
+                   UserShare* share, int64* transaction_version);
   virtual ~WriteTransaction();
 
   // Provide access to the syncable transaction from the API WriteNode.
   virtual syncable::BaseTransaction* GetWrappedTrans() const OVERRIDE;
   syncable::WriteTransaction* GetWrappedWriteTrans() { return transaction_; }
 
  protected:
   WriteTransaction() {}
 
   void SetTransaction(syncable::WriteTransaction* trans) {
-      transaction_ = trans;
+    transaction_ = trans;
   }
 
  private:
   void* operator new(size_t size);  // Transaction is meant for stack use only.
 
   // The underlying syncable object which this class wraps.
   syncable::WriteTransaction* transaction_;
 
   DISALLOW_COPY_AND_ASSIGN(WriteTransaction);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_WRITE_TRANSACTION_H_