Properly type stack frames as eval or file
Summary:
Xdebug lets us type stack frame elements as 'eval', in addition to 'file', and this is useful for various reasons, for example, we will want to expose this in the UI of Nuclide.
This diff adds logic to walk the whole call stack to find the oldest frame which qualifies as an 'eval' frame, meaning it has no m_name set, but has a parent.
Reviewed By: alexmalyshev
Differential Revision:
D3453570
fbshipit-source-id:
b50fa733300b4d1aa6d12ef2a7ec20a18beeb405