DevTools: [Shadow DOM] Display author shadow roots regardless of the setting value

R=pfeldman@chromium.org, eustas, pfeldman, vsevik
BUG=350511

Review URL: https://codereview.chromium.org/196133004

git-svn-id: svn://svn.chromium.org/blink/trunk@169122 bbb929c8-8fbe-4397-9dbb-9b2b20218538