We're rewriting internal/encoding/json. So, make a copy of it first in
order not to break encoding/jsonpb package.
Change-Id: I8b63c468d3f432102d2af4db22a7549998ce3876
Reviewed-on: https://go-review.googlesource.com/c/164642
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
This does not handle extensions, messagesets, and well-known types yet.
Change-Id: I2786c429f490fe8c57f3f85cd25058d936b58bf7
Reviewed-on: https://go-review.googlesource.com/c/162637
Reviewed-by: Damien Neil <dneil@google.com>