Use new match Functor ElementTraversal API in  DOMSiblingTraversalStrategy

Use new match Functor ElementTraversal API in  DOMSiblingTraversalStrategy to
simplify the code a bit.

R=adamk@chromium.org, esprehn@chromium.org

Review URL: https://codereview.chromium.org/475023002

git-svn-id: svn://svn.chromium.org/blink/trunk@180299 bbb929c8-8fbe-4397-9dbb-9b2b20218538