Hide names of internal classes from the user by mapping them to the documented

runtime/lib/error.cc

Index: runtime/lib/error.cc
===================================================================
--- runtime/lib/error.cc	(revision 9744)
+++ runtime/lib/error.cc	(working copy)
@@ -65,7 +65,7 @@
   const String& dst_name = String::CheckedHandle(arguments->At(3));
   const String& malformed_error = String::CheckedHandle(arguments->At(4));
   const String& src_type_name =
-      String::Handle(Type::Handle(src_value.GetType()).Name());
+      String::Handle(Type::Handle(src_value.GetType()).UserVisibleName());
   Exceptions::CreateAndThrowTypeError(location, src_type_name,
                                       dst_type_name, dst_name, malformed_error);
 }