Summary:
This is a part of D1164. DWARFCompileUnit is not that lightweight
to copy it around, and we want it to own corresponding .dwo compile unit
eventually.
Reviewers: echristo
Reviewed By: echristo
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1298
llvm-svn: 189089