Remove several obsolete methods from the WebAutofillClient interface.

(This is a second attempt to land this, now that the Chromium repository has
 been properly readied.)

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

Review URL: https://codereview.chromium.org/127593002

git-svn-id: svn://svn.chromium.org/blink/trunk@164674 bbb929c8-8fbe-4397-9dbb-9b2b20218538