
DDS was temporarily pinned to 4.1.0 because 4.2.0 triggered some test failures (see https://github.com/flutter/flutter/pull/147250). Those failures should be fixed by vm_service 14.2.2, so this unpins DDS and rolls both of these packages (along with devtools_shared, which is a DDS dependency). (If the bot updates vm_service before this is done, I can rebase over that will reduce the size of this PR to just a few files)
Image List
An example that sets up a local HTTP server for serving one image then creates a single flutter widget with five copies of requested image and prints how long the loading took.
This is used in [$FH/flutter/devicelab/bin/tasks/image_list_reported_duration.dart] test.