23767 Migrate to use the published metrics_center (cla: yes)

23769 [web] Fix shadow rendering using boxshadow due to webkit repaint area bug (cla: yes, waiting for tree to go green)

23770 Roll Dart SDK from c4214e6daaac to 4a6764bf28c2 (4 revisions) (cla: yes, waiting for tree to go green)

23772 Roll Skia from bde06cc511d2 to f3087d8297fe (7 revisions) (cla: yes, waiting for tree to go green)

23773 [web] Fix drawPoints api crash when strokeWidth is not specified. (cla: yes)

23775 skip flaky test (cla: yes, platform-ios)