sync: Start moving away from PREV_ID and NEXT_ID

sync/syncable/entry.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 SYNC_SYNCABLE_ENTRY_H_
 #define SYNC_SYNCABLE_ENTRY_H_
 
 #include "sync/base/sync_export.h"
 #include "sync/syncable/entry_kernel.h"
 
@@ skipping 87 matching lines @@
     return kernel_->ref(field);
   }
   inline bool Get(BitTemp field) const {
     DCHECK(kernel_);
     return kernel_->ref(field);
   }
 
   ModelType GetServerModelType() const;
   ModelType GetModelType() const;
 
+  Id GetPredecessorId() const;
+  Id GetSuccessorId() const;
+
   inline bool ExistsOnClientBecauseNameIsNonEmpty() const {
     DCHECK(kernel_);
     return !kernel_->ref(NON_UNIQUE_NAME).empty();
   }
 
   inline bool IsRoot() const {
     DCHECK(kernel_);
     return kernel_->ref(ID).IsRoot();
   }
 
@@ skipping 32 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(Entry);
 };
 
 std::ostream& operator<<(std::ostream& os, const Entry& entry);
 
 }  // namespace syncable
 }  // namespace syncer
 
 #endif  // SYNC_SYNCABLE_ENTRY_H_