GitLab

This makes CalculateVisibleRects try to re-use the to_target and
from_target transforms stored in transform nodes whenever it needs to
compute a transform. Since these baked transforms incorporate the
target's sublayer scale, the fallback path now also includes sublayer
scale for consistency.

Testing locally on a z620, this improves property tree computation time
by 7% on Gmail, and by 20% on rAF-driven poster circle.

BUG=474725

Review URL: https://codereview.chromium.org/1060413002

Cr-Commit-Position: refs/heads/master@{#324122}