22085 Implement Scene.toImage() in CanvasKit mode. (cla: yes, platform-web)

22086 Add metrics scripts in preparation to move the builder to LUCI. (cla: yes)

22087 Roll Fuchsia Mac SDK from zDfaxkqlv… to kCSI3uPt1… (cla: yes, waiting for tree to go green)

22089 Fix _lerpInt precision bug (cla: yes)

22090 Roll Dart SDK from a3d902d8598e to ae67d4be7d8e (9 revisions) (cla: yes, waiting for tree to go green)

22091 Remove some obsolete code from RuntimeController (cla: yes, waiting for tree to go green)