Move Toolbar into Bramble #627
Description
We went to great lengths to not have the toolbar for Thimble live inside Bramble. Right now, it lives outside the Bramble iframe, and we have a bunch of complicated postMessage based APIs for enabling/disabling things, setting/getting state, and handling events between the two:
When we first did it this way, we were worried about diverging so much from upstream work by Adobe. In the end, that's not really a big issue. However, we have a bunch of bugs that are the result of this not being perfect, for example https://github.com/mozilla/thimble.mozilla.org/issues/686, and there's a bunch of state that we don't track properly.
@gideonthomas suggested that we consider moving the toolbar into the iframe, and have it live with Bramble vs. Thimble. There's actually nothing in the toolbar that is security sensitive, so it would be smart to do so.
One question to consider here is whether to continue to support the iframe API we have now, and whether to make this toolbar optional. For any downstream users of Bramble (code.org comes to mind, but there are others), we don't want to force them to use our UI. At the same time, we don't want to maintain overly complicated API code that we don't really need.
This work probably shouldn't start until May, since it would be really disruptive to the current group of Seneca students. It's also not high priority, since things are working right now.