21816 Roll Skia from 2e0c70dc9c3e to 7bbdde059685 (10 revisions) (cla: yes, waiting for tree to go green)

21817 Enable clipRRect for android platform view hybrid composition (cla: yes, platform-android, waiting for tree to go green)

21819 Add a style note about Linux embedding style (cla: yes, waiting for tree to go green)

21820 Enable loading snapshots with sound null safety enabled. (cla: yes, waiting for tree to go green)

21830 Roll Dart SDK from a3b62f366529 to 4226116043f5 (1 revision) (cla: yes, waiting for tree to go green)