[FastTextAutosizer] Don't autosize single rows of links

This patch checks TextAutosizer::containerShouldBeAutosized in
FastTextAutosizer::inflate which prevents inflation of single rows
of links.

We now pass 7 more tests!

Unfortunately, due to crbug.com/333124 it is not obvious that this
patch fixes header-links-autosizing.html (and several other tests) as
well as wikipedia's header links.

BUG=

Review URL: https://codereview.chromium.org/133093002

git-svn-id: svn://svn.chromium.org/blink/trunk@164906 bbb929c8-8fbe-4397-9dbb-9b2b20218538