Add proto for TLS error assistant, refactor proto generator code.

This CL adds binary_proto_generator.py which contains code to generate
binary protobufs from ascii protobufs. SafeBrowsing download file types
list and TLS error assistant use this generator to generate their
respective binary protos.

BUG=640835
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2567483002
Cr-Commit-Position: refs/heads/master@{#439292}
10 files changed