Add WPT coverage of Sec-CH-Width
This patch adds WPT coverage of Sec-CH-Width:
https://wicg.github.io/responsive-image-client-hints/#sec-ch-width
Bug: 335630145
Change-Id: I329d39c8d0d259e9226e64468a083513c555322b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5523418
Reviewed-by: Traian Captan tcaptan@chromium.org
Commit-Queue: Philip Rogers pdr@chromium.org
Cr-Commit-Position: refs/heads/main@{#1300292}