Expose the CSSSupportsRule interface object

It appears to be an historical accident that this is not exposed, as
originally one had to explicitly expose interface objects:
https://chromiumcodereview.appspot.com/14179013

Firefox Nightly also exposes this.

Review URL: https://codereview.chromium.org/797853002

git-svn-id: svn://svn.chromium.org/blink/trunk@187116 bbb929c8-8fbe-4397-9dbb-9b2b20218538
5 files changed
tree: d21b79f1fd5fedbc532735c946c89d886d1530ba
  1. third_party/