TextAutosizer: fix second-pass container autosizing.

This patch adds a check to properly autosize containers inside
stale clusters during the second pass of the algorithm (see
crbug.com/335589 for more details). Additionaly this patch
removes an unused method and adds a test.

BUG=335589,334228
NOTRY=true

Review URL: https://codereview.chromium.org/141903002

git-svn-id: svn://svn.chromium.org/blink/trunk@165757 bbb929c8-8fbe-4397-9dbb-9b2b20218538