Summary:
It will be used to pass around things like Logger and Tracer throughout
clangd classes.
Reviewers: sammccall, ioeric, hokein, bkramer
Reviewed By: sammccall
Subscribers: klimek, bkramer, mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D40485
llvm-svn: 320468
Ilya Biryukov