22794 Add package:file to DEPS (cla: yes)

22801 Roll Dart SDK from 7a2a3968ef53 to e9a03fd98faa (5 revisions) (cla: yes, waiting for tree to go green)

22802 Roll Skia from 4c6f57a23e63 to a927771c9cce (10 revisions) (cla: yes, waiting for tree to go green)

22803 Roll Skia from a927771c9cce to 7b776b514933 (3 revisions) (cla: yes, waiting for tree to go green)

22804 Roll buildroot and benchmark (cla: yes, waiting for tree to go green)