Fix the lack of damage tracking for root layer position changes in BGPT.

Previous to this CL, if the position of a layer changed, and that layer
was the root layer targeting a render surface, the old location of the
surface was not damaged in the *parent* render surface. With BGPT disabled,
this was masked by transform_changed being set at [1], which triggered
the conditional at [2] and caused the old location to be damaged. With
BGPT enabled, transform_changed is never set. The new logic here detects
LayerPropertyChangedNotFromPropertyTrees() for a root layer, and
triggers the conditional at [2].

[1] https://cs.chromium.org/chromium/src/cc/layers/layer.cc?rcl=4b6a562c7bde8700fe66eda5d3f65b3e48750ef2&l=758
[2] https://cs.chromium.org/chromium/src/cc/trees/damage_tracker.cc?rcl=8c9c36220d67ee9ea6a4d830b7020cceb52e5aeb&l=449

Bug: 939282
Change-Id: I946c1d85baf7096ef6199efc811cafe55798d930
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1533176
Commit-Queue: Mason Freed <masonfreed@chromium.org>
Commit-Queue: enne <enne@chromium.org>
Reviewed-by: enne <enne@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Auto-Submit: Mason Freed <masonfreed@chromium.org>
Cr-Commit-Position: refs/heads/master@{#644099}
5 files changed