GitLab

This CL adds a stream request parser to parse StreamBody messages sent by
a server that handles protobuf over HTTP. It will later be used by
ProtobufHttpClient to handle stream request.

It also makes ProtobufHttpStatus something similar to grpc::Status, that
has a unified code and message, as the error code can now come from three
different places.

Bug: 1103416
Change-Id: I62c4d9c74cc17a9b10244fa1013372308ec9d4a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2305113
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790063}