Invalidation set features are not skippable.

Ids, attributes, tag names, and custom pseudo elements are handled as
invalidation set features and not skippable. Should be unnecessary to check
for them in isSkippableComponentForInvalidation.

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

Review URL: https://codereview.chromium.org/450293002

git-svn-id: svn://svn.chromium.org/blink/trunk@180463 bbb929c8-8fbe-4397-9dbb-9b2b20218538