Remove several obsolete methods from the WebAutofillClient interface.

BUG=330077
TEST=compiles
R=abarth@chromium.org

Review URL: https://codereview.chromium.org/119573004

git-svn-id: svn://svn.chromium.org/blink/trunk@164349 bbb929c8-8fbe-4397-9dbb-9b2b20218538