72755 Migrate some sample code to NNBD [2] (a: null-safety, cla: yes, d: api docs, d: examples, documentation, f: cupertino, framework, team, waiting for tree to go green)

72756 run framework unit tests on html backend (cla: yes, team, waiting for tree to go green)

72761 Build iOS apps using Swift Packages (cla: yes, d: examples, platform-ios, t: xcode, team, tool)

72764 Force plugins to inherit minimum macOS version from Flutter app (cla: yes, platform-mac, team, tool)

72765 [devicelab] Add results path flag to test runner (cla: yes, team, waiting for tree to go green)

72792 Migrated some services and widgets doc comments to null safety. (cla: yes, framework, team, waiting for tree to go green)