Bug 1638152 - Inform transform value in the clip rectangle and the offset from the...

Bug 1638152 - Inform transform value in the clip rectangle and the offset from the reference frame for the partial pre-render check on WebRender. r=botond

On WebRender there is no layer tree structures so that we can't accumulate
transform values up to the nearest APZ's scroll layer by walking up the layer
tree, or we can't tell a given transform animation is inside a perspective layer
to decide whether we need to apply the offset from the reference frame or not
[1]. So we get the accumulated transform by using
nsLayoutUtils::GetTransformToAncestor on the main-thread and inform it to the
compositor thread, and also inform the offset which is set conditionally [2]
so that we don't need to tell whether the transform animation is inside a
perspective layer or not on the compositor thread.

I am not yet 100% sure that these values are same both on WebRender and non
WebRender in all cases, once after partial pre-rendering transforms have
been used in the wild well enough and any problem has not appeared, even if
there are problems we should fix them then the non WebRender version should
eventually use this same setup instead of walking up the layer tree.

[1] https://searchfox.org/mozilla-central/rev/85ae3b911d5fcabd38ef315725df32e25edef83b/gfx/layers/CompositorAnimationStorage.cpp#273-275
[2] https://searchfox.org/mozilla-central/rev/85ae3b911d5fcabd38ef315725df32e25edef83b/layout/painting/nsDisplayList.cpp#7879-7891

Differential Revision: https://phabricator.services.mozilla.com/D83201