Make "using namespace" a PRESUBMIT error.

Bug: 82078
Change-Id: Ibc9405d903008c5bebf04f558e1b2c42ba5ced4d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879997
Reviewed-by: Daniel Cheng <[email protected]>
Commit-Queue: Peter Kasting <[email protected]>
Cr-Commit-Position: refs/heads/master@{#709655}
2 files changed