Remove redundant typesetting checks from Font::width()

Minor cleanup: Font::codePath() already selects ComplexPath whenever
typesettingFeatures are present (our SimplePath doesn't support kerning
and ligatures), so there's no need to duplicate that test in width().

R=schenney@chromium.org,jbroman@chromium.org,eae@chromium.org

Review URL: https://codereview.chromium.org/401123005

git-svn-id: svn://svn.chromium.org/blink/trunk@178557 bbb929c8-8fbe-4397-9dbb-9b2b20218538