When BGPT is enabled we recalculate compositing reasons for animation for each type of property tree node which results in a lot of repeated calculations:

https://cs.chromium.org/search/?q=file:blink/renderer/core/paint/paint_property_tree_builder.cc+CompositingReasonFinder::CompositingReasonsForAnimation&sq=package:chromium&type=cs

This resulted in the performance regression in issue 909054. If we are using all animation reasons as animation compositing triggers for all property node types, we should compute the animation reasons for compositing once and re-use it when determining if/why to create each node type.

Ultimately this could be resolved by a proper solution to detecting when to start animations (tracked by issue 900241).