[headless] Create headless/ folder
[headless] Create headless/ folder

Create top-level headless/ folder and OWNERS for it.

BUG=546953

Review URL: https://codereview.chromium.org/1433933007

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#360095}

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