Remove the old text autosizer

This patch removes the old text autosizer. Long live the fast text
autosizer!*


*which we should rename to TextAutosizer in a followup patch.

BUG=385380

Review URL: https://codereview.chromium.org/346603005

git-svn-id: svn://svn.chromium.org/blink/trunk@179181 bbb929c8-8fbe-4397-9dbb-9b2b20218538