Un-deprecate Attr.nodeValue and Attr.textContent

These are both back in the DOM Standard:
https://dom.spec.whatwg.org/#attr

Spec bugs:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=26596
https://www.w3.org/Bugs/Public/show_bug.cgi?id=27363

These were deprecated in Blink before any of this happened:
https://codereview.chromium.org/253843002

It turns out that the usage of nodeValue in particular is far too high:
https://www.chromestatus.com/metrics/feature/timeline/popularity/348
https://www.chromestatus.com/metrics/feature/timeline/popularity/349

We're probably stuck with both forever, but they're trivial to support.

Keep the counters just to see if things change over time.

BUG=305105

Review URL: https://codereview.chromium.org/739193002

git-svn-id: svn://svn.chromium.org/blink/trunk@185606 bbb929c8-8fbe-4397-9dbb-9b2b20218538
53 files changed
tree: 02da98196186ac62534d630f4a548e4dab9b8d09
  1. third_party/