Remove SkPath::getBounds workaround for bitmap fonts

Remove an old workaround for bitmap font measurements as it is no
longer needed now that Skia has been updated.

TEST=Covered by existing tests
R=leviw@chromium.org
BUG=

Review URL: https://codereview.chromium.org/111043003

git-svn-id: svn://svn.chromium.org/blink/trunk@164475 bbb929c8-8fbe-4397-9dbb-9b2b20218538