Change nullptr to Empty List

components/sync/model/model_type_debug_info.cc

Index: components/sync/model/model_type_debug_info.cc
diff --git a/components/sync/model/model_type_debug_info.cc b/components/sync/model/model_type_debug_info.cc
index 0b362b82593d98b1cd6ba84102fa502acb626be1..ad8ca563f517cb1787642db879f63b5ec5865d4c 100644
--- a/components/sync/model/model_type_debug_info.cc
+++ b/components/sync/model/model_type_debug_info.cc
@@ -99,7 +99,7 @@ void ModelTypeDebugInfo::MergeDataWithMetadata(
   rootnode->SetString("NON_UNIQUE_NAME", type_string);
   all_nodes->Append(std::move(rootnode));
 
-  callback.Run(processor->type_, nullptr);
+  callback.Run(processor->type_, base::MakeUnique<ListValue>());
 }
 
 }  // namespace syncer