Made old dart:json library use convert to parse JSON.

runtime/vm/bootstrap.h

Index: runtime/vm/bootstrap.h
diff --git a/runtime/vm/bootstrap.h b/runtime/vm/bootstrap.h
index 8d77617a527782a8b84c686b010044a843e17994..6ebc8124637e56bb02d74bcbd24314939ed66c05 100644
--- a/runtime/vm/bootstrap.h
+++ b/runtime/vm/bootstrap.h
@@ -37,8 +37,8 @@ class Bootstrap : public AllStatic {
   static const char* corelib_patch_paths_[];
   static const char* collection_patch_paths_[];
   static const char* collection_dev_patch_paths_[];
+  static const char* convert_patch_paths_[];
   static const char* isolate_patch_paths_[];
-  static const char* json_patch_paths_[];
   static const char* math_patch_paths_[];
   static const char* mirrors_patch_paths_[];
   static const char* typed_data_patch_paths_[];