Add CSS parsing for experimental touch-action-delay feature.

Carried over changes from https://codereview.chromium.org/22113002/

Intent to Implement:
https://groups.google.com/a/chromium.org/forum/#%21msg/blink-dev/mDSwpxfdrdA/zA7W8PLPo4oJ

Design Doc:
https://docs.google.com/a/chromium.org/document/d/1CV2AXyrdPdGSRypAQcfGrgQVuWYi50EzTmVsMLWgRPM/edit

BUG=297781

Review URL: https://codereview.chromium.org/26561003

git-svn-id: svn://svn.chromium.org/blink/trunk@159897 bbb929c8-8fbe-4397-9dbb-9b2b20218538