Make MarkupAccumulator non-copyable.

BUG=

Review URL: https://codereview.chromium.org/116283003

git-svn-id: svn://svn.chromium.org/blink/trunk@164353 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove obsolete code in PopupListBox for handling Autofill popup menu rendering.

BUG=330077
TEST=<select> menus continue to render correctly
R=tkent@chromium.org

Review URL: https://codereview.chromium.org/119733003

git-svn-id: svn://svn.chromium.org/blink/trunk@164354 bbb929c8-8fbe-4397-9dbb-9b2b20218538