Revert r155355 as it caused CJK glyphs to render as boxes for users with Droid Sans installed.

I've filed http://crbug.com/285303 about fixing the underlying issue
that this change made more obvious.

Unfortunately this change will cause a large perf regression for CJK text.
It's just reverting a large perf gain we got with the previous change.

This reverts:
https://codereview.chromium.org/21497002

BUG=272006
R=abarth@chromium.org

Review URL: https://codereview.chromium.org/23622018

git-svn-id: svn://svn.chromium.org/blink/trunk@157226 bbb929c8-8fbe-4397-9dbb-9b2b20218538