[1/N] Add DIR_METADATA files to directories under //third_party/

Generate DIR_METADATA files and remove metadata from OWNERS
files for directories under //third_party/.

R=yfriedman@chromium.org

Bug: 1113033
Change-Id: If7ee35e80c00f427198e6f30bc42e7e921fee708
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2572725
Auto-Submit: Gavin Mak <gavinmak@google.com>
Commit-Queue: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833720}
GitOrigin-RevId: db0d0146b4e7a28fe04bd96b0c4cb1e814f7aa65
2 files changed