I can't do responsible disclosure when there are tens of thousands of apps using webView. The number of vulnerable apps is way too high for any kind of responsible disclosure.
If it was me, I would have notified Apple and all of the companies who have bug bounty programs.
http://support.apple.com/kb/HT6162
I reported CVE-2013-6835. They fixed Facetime-Audio from Safari, but not from other browsers (yet?). This is quite a wide issue. I do not think letting every individual developer know is feasible. I did it for a few bad issues, but there's a limit to what can be done.
And a lot of these can be found in a matter of minutes anyways.