Count DOMImplementation.hasFeature usage and cases where it returns false

This is in order to support the spec discussion:
http://lists.w3.org/Archives/Public/www-dom/2014JanMar/0031.html
http://lists.w3.org/Archives/Public/www-svg/2014Jan/0042.html

BUG=335301

Review URL: https://codereview.chromium.org/141363002

git-svn-id: svn://svn.chromium.org/blink/trunk@165299 bbb929c8-8fbe-4397-9dbb-9b2b20218538