Change BreakingContext to use right dir for width

BreakingContext::handleText currently uses the unicode direction from
the BidiResolver. This works fine for characters with strong
directionality but fails for all other directionalities as the dir
value has not yet been resolved (by the UBA).
Instead change it to use the version of constructTextRun that
resolved the directionality from the text content.

TEST=fast/text/international/rtl-text-wrapping.html
BUG=348554
R=dglazkov@chromium.org

Review URL: https://codereview.chromium.org/190623003

git-svn-id: svn://svn.chromium.org/blink/trunk@168841 bbb929c8-8fbe-4397-9dbb-9b2b20218538