This came up while doing commit 3fe737215d43: ("third_party/zlib: fix
for "gn check""), at https://chromium-review.googlesource.com/508355

zip and compression_utils are libraries built on top of zlib and base,
and they don't really belong to third_party/zlib. As a first move
into pulling them out of third_party, we are extracting their
targets out of zlib's BUILD.gn file.

BUG=None

Change-Id: I927d212b8e68ddef1961e2f1971eee5bcf0a6df7
Reviewed-on: https://chromium-review.googlesource.com/509510


Reviewed-by: Matt Sarett <msarett@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Thiago Farina <tfarina@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#473595}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: d8a8a07cc7b4196d00c7ecb3eeb96671cd189dea