Lib: add message event types and PerformanceObserver

[pmwhite]

No description provided.

[hhugo]

should we also bind PerformanceObserver.supportedEntryTypes ?

[hhugo]

Also, can you rebase the branch ? The changelog will need to be updated.

[pmwhite]

Sorry, took me a while to get back to this PR. I attempted the rebase, and now apparently there are 72 commits. I don't know why, because my fork only looks like it's 7 commits ahead.

[hhugo]

It looks like you introduced a merge commit in your branch. Try git rebase -i to only rebase your commits and dropping the merge commit on the way.

[pmwhite]

I tried to fix this with git rebase -i, but it seemed like I think my previous actions had made the fix more complicated than just removing the merge commit. I figured it would be easier to reset my fork to upstream master and re-apply the diff of this PR as one commit. Sadly, it had the side-effect of closing this PR automaticaly, so I've re-opened it in #1164