Bug 1036949 - New API: MarkupView customization

[janodvarko]

Integration with the Inspector panel requires new platform API

See: https://bugzilla.mozilla.org/show_bug.cgi?id=1036949

Honza

[janodvarko]

@aliuk2012 this is the bug I mentioned in the morning. I have committed my local changes I did when I've been testing the platform patch. The platform patch landed and is in Nightly now, so I am closing this one.

It would be great to test this yet.

Honza