registerProtocolHandler and registerContentHandler, as defined in the HTML5 spec, should be supported by WebKit.
Both methods landed in r50477, following bug 29651. This exposed the methods, but as no port implemented them, they were rolled out in r62834.
More recently, James Kozianski said he would have a look at implementing this. I've added him to the cc list.
JS bindings for registerProtocolHandler were landed in bug 44740, and I'm working on an implementation for Chromium here http://codereview.chromium.org/6410115/
Is there any way to roll the 'registerContentHandler' in again?
I will implement EFL port layer for the API.
Please let me know how to roll the API in again.
*** This bug has been marked as a duplicate of bug 73177 ***