Revert 160800 Reland: Implement new Blink IDL attribute [SetReference]

TBR=kouhei@chromium.org
BUG=307341

Review URL: https://codereview.chromium.org/52313002

git-svn-id: svn://svn.chromium.org/blink/trunk@160925 bbb929c8-8fbe-4397-9dbb-9b2b20218538