Run a try job with this patch and look at the failures.
https://chromium-review.googlesource.com/c/chromium/src/+/1075891/3
The following can be rebaselined with small changes and no apparent failure:
animations/rotate-transform-equivalent.html
compositing/3d-corners.html
compositing/direct-image-compositing.html
compositing/flat-with-transformed-child.html
compositing/lots-of-img-layers-with-opacity.html
compositing/lots-of-img-layers.html
compositing/perpendicular-layer-sorting.html
compositing/perspective-interest-rect.html
compositing/video-frame-size-change.html
compositing/geometry/fixed-position-transform-composited-page-scale-down.html
compositing/geometry/fixed-position-transform-composited-page-scale.html
compositing/geometry/layer-due-to-layer-children-deep.html
compositing/geometry/layer-due-to-layer-children.html
compositing/geometry/vertical-scroll-composited.html
compositing/masks/mask-with-removed-filters.html
compositing/overflow/border-radius-styles-with-composited-child.html
compositing/overflow/mask-with-filter.html
compositing/overflow/nested-render-surfaces-with-rotation.html
compositing/overflow/scaled-overflow.html
compositing/overflow/tiled-mask.html
compositing/reflections/nested-reflection-anchor-point.html
css3/blending/background-blend-mode-overlapping-accelerated-elements.html fast/borders
fast/clip
media/video-layer-crash.html
media/video-zoom-controls.html
paint/invalidation/scroll/scrollbar-damage-and-full-viewport-repaint.html
transforms/3d/
virtual/android/fullscreen/full-screen-iframe-allowed-video.html
virtual/android/fullscreen/video-controls-timeline.html
virtual/android/fullscreen/video-scrolled-iframe.html
virtual/prefer_compositing_to_lcd_text/compositing/overflow/border-radius-styles-with-composited-child.html
virtual/prefer_compositing_to_lcd_text/compositing/overflow/mask-with-filter.html
virtual/prefer_compositing_to_lcd_text/compositing/overflow/nested-render-surfaces-with-rotation.html
virtual/prefer_compositing_to_lcd_text/compositing/overflow/scaled-overflow.html
virtual/prefer_compositing_to_lcd_text/compositing/overflow/tiled-mask.html
Comment 1 by schenney@chromium.org
, Aug 20