sync: Better iteration in GenericChangeProcessor

sync/internal_api/public/base_node.h

Index: sync/internal_api/public/base_node.h
diff --git a/sync/internal_api/public/base_node.h b/sync/internal_api/public/base_node.h
index 7cf2edb2af257ab15ebf97cb2afaa13afeccf5e9..094fe7d66e9e89f7bfbc9378f27212bfc6da09cf 100644
--- a/sync/internal_api/public/base_node.h
+++ b/sync/internal_api/public/base_node.h
@@ -191,6 +191,11 @@ class SYNC_EXPORT BaseNode {
   // children, return 0.
   int64 GetFirstChildId() const;
 
+  // Returns the IDs of the children of this node.
+  // If this type supports user-defined positions the returned IDs will be in
+  // the correct order.
+  void GetChildIds(std::vector<int64>* result) const;
+
   // Returns the total number of nodes including and beneath this node.
   // Recursively iterates through all children.
   int GetTotalNodeCount() const;