Adds a new chrome-only MutationObserverInit option called nativeAnonymousChildList
that will cause a mutation to fire when a native anonymous root is bound or unbound
In bug 1195180 we plan to tick animations from their timeline where they
are stored in a hashtable. As a result, we will not visit them in order of
their associated target element (indeed, part of the reason we are doing
this is to support animations that do not have, or even have multiple target
elements).
The current animation mutation observer batching mechanism, however, assumes
that we visit each target element in turn and make all the necessary work at
once. In order to support visiting animations in a potentially random order
this patch reworks the animation mutation observer batching mechanism so that
it can support batching multiple elements at once.
This patch is a fairly minimal rename of the AnimationPlayer interface. It
leaves a bunch of local variables and helper classes still using the word
"player". These will be addressed in subsequent patches that don't require DOM
peer review.
There are still some other references to "source" in AnimationPlayer such as
HasInPlayerSource and UpdateSourceContent. These are renamed in a subsequent
patch (that doesn't require DOM peer review).
We define KeyframeEffectReadonly in KeyframeEffect.cpp since Web Animations also
defines KeyframeEffect and when we come to implement that I expect we'll define
it in the same class, maybe even using the same object.
This patch also adds a few missing includes in places where
KeyframeEffectReadonly is used so that we're not just cargo-culting it in.
