Adopt unsigned long constant type into DOM

This CL made DOM understand unsigned long type what previously
had been recognized as int.

In addition, with this change, a failed test case will be passed in
http://w3c-test.org/dom/traversal/NodeFilter-constants.html

TEST=LayoutTests/fast/dom/constants.html

Behavior in other browsers:
*)FF: PASS
*)IE: PASS

Review URL: https://codereview.chromium.org/387263003

git-svn-id: svn://svn.chromium.org/blink/trunk@178025 bbb929c8-8fbe-4397-9dbb-9b2b20218538