Copy the necessary build overrides from Chromium

These are the copies of files necessary for GN build, taken from
Chromium src/build_overrides.

BUG=https://bugs.chromium.org/p/nativeclient/issues/detail?id=4371
R=mcgrathr@chromium.org

Review URL: https://codereview.chromium.org/1934803002 .
4 files changed
tree: 591f2ea005736f5f9af72a8deee6bf8564dfeb5a
  1. README.md
  2. build.gni
  3. codereview.settings
  4. gtest.gni
README.md

Build overrides in GN

This directory is used to customize settings for repos that are DEPS'ed in and shared with Chromium.

build.gni was copied verbatim from Chromium‘s copy of //build_overrides and should be kept in sync with Chromium’s version.

gtest.gni contains modification which are specific to Native Client.