Currently we avoid posting animation restyles when unbinding an element by
removing the element from the document before deleting its animation
collections. As a result, when canceled animations go to post a restyle, they
can't find a pres context and give up posting a restyle.
However, this is problematic for two reasons:
* It means we can't remove such canceled animations from the
PendingAnimationTracker if they are present there (i.e. it regresses the fix
from bug 1223445).
* It means we can't post cancel events for such animations/transitions since we
can't lookup the appropriate AnimationEventDispatcher.
In the next patch in this series we will change that order to fix the above
problems but before we do that, we need to introduce another mechanism to make
sure that we don't post restyles when unbinding an element or else we will
regress bug 1396041.
This patch does that by introducing a flag which causes us to not post restyles
when we are doing DOM surgery. For all other cases we actually _do_ need to post
restyles in order to update the style correctly.
Without this patch, layout/style/crashtests/1396041.html would fail after
applying the next patch in this series.
Differential Revision: https://phabricator.services.mozilla.com/D28021
--HG--
extra : moz-landing-system : lando
Brian Birtles