It's actually mentioned at the bottom of the article: Timeline: December 2, 2014 — Reported the vulnerability to the Android security, @natashenka confirme

It's actually mentioned at the bottom of the article: Timeline: December 2, 2014 — Reported the vulnerability to the Android security, @natashenka confirmed the repro works January 6, 2015 — Response form Android security saying that the fix was pushed in mid-December, I checked that the repro stopped working on all my phones January 9, 2015 — Public disclosure