Move constants out of headers and into implementation files.

As a result, also use std::unique_ptr<char[]> instead of char[] class
members. This makes zip archiver more closely follow chromium style.

BUG=889703

Change-Id: I551557958beff280e344134f15be20a406fb5ea8
Reviewed-on: https://chromium-review.googlesource.com/1242643
Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Anand Mistry <amistry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594621}
6 files changed