[webkit-dev] Update on removing webkitPostMessage

[Adam Barth]

Based on our discussion in September, the Chromium port has been
shipping for a while with webkitPostMessage compiled out.  We've been
monitoring our support channels and haven't found any reports of
compatibility problems.  (By way of comparison, we did find some
compatibility problems with removing WebKitBlobBuilder, but we were
able to resolve those with evangelism.)

Based on this experience and my scouring the web for uses of
webkitPostMessage, I think it's safe to remove the prefixed version of
the API:

https://bugs.webkit.org/show_bug.cgi?id=105910

In my web searches, I did manage to find a couple developers who were
using the prefixed version of the API, but I contacted them directly
and they've now changed their content to use the identical
(unprefixed) postMessage API.

Thanks,
Adam