Take the hatchet to WidthIterator::applyFontTransforms()

After https://src.chromium.org/viewvc/blink?view=rev&revision=176027 it
became clear that applyFontTransforms() is an elaborate no-op: we're
just re-applying the same advances saved in advanceInternal(), without
any intervening mutations.

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

Review URL: https://codereview.chromium.org/382033002

git-svn-id: svn://svn.chromium.org/blink/trunk@177889 bbb929c8-8fbe-4397-9dbb-9b2b20218538