Process and non-process managers have different script loader interfaces
(ProcessScriptLoader/GlobalProcessScriptLoader vs FrameScriptLoader). The WebIDL
conversion used the same interface for some process and
non-process managers, but because of the different script loader interfaces they really
should be using separate interfaces.
The change in browser_net_view-source-debugger.js is needed because we now use WebIDL callbacks for MessageListener, and they add async creation stack frames.
