Reland "Modify supercluster multiplier logic".

This relands http://crrev.com/231663006, which was reverted in http://crrev.com/235993003 due to http://crbug.com/362975.

The logic in maxClusterWidthProvider has been updated to avoid returning null.

BUG=361749
R=pdr@chromium.org

Review URL: https://codereview.chromium.org/237063007

git-svn-id: svn://svn.chromium.org/blink/trunk@171517 bbb929c8-8fbe-4397-9dbb-9b2b20218538