DevTools: move SettingsUI back into ui/ component.
It should not have moved in r174758.

TBR=dgozman

Review URL: https://codereview.chromium.org/302763002

git-svn-id: svn://svn.chromium.org/blink/trunk@174879 bbb929c8-8fbe-4397-9dbb-9b2b20218538