Remove WebPasswordFormData and util files

Functioins in there files have been rewritten in
components/autofill/content/renderer/password_form_conversion_utils.
This is to refact old Blink code on WebPasswordFormData and utils files.

R=gcasto@chromium.org, tkent
BUG=None

Review URL: https://codereview.chromium.org/246233005

git-svn-id: svn://svn.chromium.org/blink/trunk@172999 bbb929c8-8fbe-4397-9dbb-9b2b20218538