Add Autofill preview support for <select> input fields

The <select> preview is set with yellow background inline with Input and
TextArea Element preview css settings.

R=dhollowa@chromium.org, isherman@chromium.org, jhawkins@chromium.org, tkent@chromium.org
BUG=58719

Review URL: https://codereview.chromium.org/138433002

git-svn-id: svn://svn.chromium.org/blink/trunk@169476 bbb929c8-8fbe-4397-9dbb-9b2b20218538