18128 [web] Workaround for compositing bug in chrome/webkit (cla: yes)

18129 Roll src/third_party/skia 8a2f29eae7a5..9588a643d96f (9 commits) (cla: yes, waiting for tree to go green)

18130 Roll src/third_party/dart e7bebea059ff..01820c20a540 (15 commits) (cla: yes, waiting for tree to go green)

18131 System mouse cursor: macOS (cla: yes)

18132 Revert again “Remove layer integral offset snapping” (cla: yes, perf: speed, severe: performance, waiting for tree to go green)