Remove the old text autosizer (2)

This is a followup to [1] which dropped the actual removal of
TextAutosizer{.h,.cpp}.

[1] https://src.chromium.org/viewvc/blink?view=rev&revision=179181

TBR=skobes
BUG=385380

Review URL: https://codereview.chromium.org/427953003

git-svn-id: svn://svn.chromium.org/blink/trunk@179188 bbb929c8-8fbe-4397-9dbb-9b2b20218538