DevTools: Add UA presets for Chrome/Opera on Win/Mac

Patch from Mathias Bynens <mathias@qiwi.be>
BUG=332751

Review URL: https://codereview.chromium.org/131703002

git-svn-id: svn://svn.chromium.org/blink/trunk@165449 bbb929c8-8fbe-4397-9dbb-9b2b20218538