DevTools: Copy disabled CSS properties to clipboard as commented out.

BUG=316532
R=aandrey@chromium.org

Review URL: https://codereview.chromium.org/88843002

git-svn-id: svn://svn.chromium.org/blink/trunk@162848 bbb929c8-8fbe-4397-9dbb-9b2b20218538