Revert "Revert "Remove <video> width and height attributes from intrisic size logic""

This reverts r160509. It was not the cause of the webkit_unit_tests failure.

TBR=philipj@opera.com

Review URL: https://codereview.chromium.org/42853002

git-svn-id: svn://svn.chromium.org/blink/trunk@160511 bbb929c8-8fbe-4397-9dbb-9b2b20218538