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This CL adds a simple HeadlessScreen implementation and removes
usage of NativeDisplayDelegate.

Bug: 891613
Change-Id: I522b500ad32358f4ec7db95e4b58b0774b4cc807
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1782558
Commit-Queue: Maksim Sisov <msisov@igalia.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#693636}