Webrender: Weird clipping of blob images during scrolling

[nical]

For example go to https://www.digitalocean.com/ and scroll slowly. You'll see the bottom of svg elements clipped if scrolling down and the top the svg clipped when scrolling up.

This wasn't happening when I was working on async blobs so the regression is at most a 5 weeks old.

[jrmuizel]

@Darkspirit do you mind trying to find a regression window for this?

[Darkspirit]

Regressed with bug 1485691, probably by #2977.
Fixed in bug 1485791 comment 5, probably by #2980.

[gw3583]

Should this be closed?

[nical]

Yes indeed!