sync: Specialize functions that fetch type root

sync/internal_api/public/write_node.h

Index: sync/internal_api/public/write_node.h
diff --git a/sync/internal_api/public/write_node.h b/sync/internal_api/public/write_node.h
index 5b47bd63de399ebeafb141659a988a4ac73cbc3b..c46e37698dbfe07ec98ae23caa3d71e1fbf00fdf 100644
--- a/sync/internal_api/public/write_node.h
+++ b/sync/internal_api/public/write_node.h
@@ -85,10 +85,10 @@ class SYNC_EXPORT WriteNode : public BaseNode {
       const BaseNode& parent,
       const std::string& client_tag);
 
-  // Each server-created permanent node is tagged with a unique string.
-  // Look up the node with the particular tag.  If it does not exist,
-  // return false.
-  InitByLookupResult InitByTagLookup(const std::string& tag);
+  // Looks up the type's root folder.  This is usually created by the sync
+  // server during initial sync, though we do eventually wish to remove it from
+  // the protocol and have the client "fake it" instead.
+  InitByLookupResult InitTypeRoot(ModelType type);
 
   // These Set() functions correspond to the Get() functions of BaseNode.
   void SetIsFolder(bool folder);