Make arguments to NamedNodeMap methods non-optional

https://dom.spec.whatwg.org/#namednodemap

This changes Web-facing behavior, but these are alredy non-optional in
IE and Firefox so it's unlikely to break the Web.

There are use counters for all of these methods:
https://www.chromestatus.com/metrics/feature/timeline/popularity/306
https://www.chromestatus.com/metrics/feature/timeline/popularity/307
https://www.chromestatus.com/metrics/feature/timeline/popularity/308
https://www.chromestatus.com/metrics/feature/timeline/popularity/309
https://www.chromestatus.com/metrics/feature/timeline/popularity/310
https://www.chromestatus.com/metrics/feature/timeline/popularity/311
https://www.chromestatus.com/metrics/feature/timeline/popularity/312

NamedNodeMap.getNamedItem() has the highest usage, around 0.7%.

Review URL: https://codereview.chromium.org/758173002

git-svn-id: svn://svn.chromium.org/blink/trunk@185985 bbb929c8-8fbe-4397-9dbb-9b2b20218538
6 files changed
tree: 49d44f8ca41143618387c8fec681b7f647c89849
  1. third_party/