Summary:
YAML serialization was used in the Proof of Concept for simplicity.
This patch replaces implements Protobuf (de) serialization of almost all
types that need to be transferred over the protocol.
Reviewers: sammccall
Reviewed By: sammccall
Subscribers: mgorny, ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, usaxena95, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D79862
