Can we detect if a url with a custom URL scheme can be handled? Why yes. Yes we can.
I had a little down time after Google IO and I wanted to scratch a long-term itch I've had. I just want to be able to copy text that is held inside images in the browser. That is all. I think it would be a neat feature for everyone. It's not easy to add functionality directly into Chrome, but I know I can take advantage of the intent system on Android and I can now do that with the Web (or at least Chrome on Android).
This is testing sharing directly from the camera app. It looks like it worked :)