Turn Client-Hints' DPR, Width and Viewport-Width on by default.
Turn Client-Hints' DPR, Width and Viewport-Width on by default.

Intent to ship thread: https://groups.google.com/a/chromium.org/d/msg/blink-dev/vvX1vCQihDE/wg6JQg9utaMJ

BUG=458983

Review URL: https://codereview.chromium.org/1262253002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@200414 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk