[kern] Refactoring.

src/hb-kern.hh

diff --git a/src/hb-kern.hh b/src/hb-kern.hh
index 99d533c..3f952fe 100644
--- a/src/hb-kern.hh
+++ b/src/hb-kern.hh
@@ -52,8 +52,7 @@
     OT::hb_ot_apply_context_t c (1, font, buffer);
     c.set_lookup_mask (kern_mask);
     c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
-    OT::hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c.iter_input;
-    skippy_iter.init (&c);
+    auto &skippy_iter = c.iter_input;
 
     bool horizontal = HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction);
     unsigned int count = buffer->len;