30162 Cherrypick #29862 for b/208763970 (platform-ios, cla: yes)

needs tests - 77 pull request(s)

27351 Add eol at end of .dart files (cla: yes, platform-web, needs tests)

28067 winuwp: Add multi-touch support (cla: yes, waiting for tree to go green, platform-windows, needs tests)

28609 Call didFailToRegisterForRemoteNotificationsWithError delegate methods in FlutterPlugin (platform-ios, cla: yes, waiting for tree to go green, needs tests)

29139 [web] Start support for Skia Gold (cla: yes, waiting for tree to go green, platform-web, needs tests)

29176 Update functions to be consistent with other code. (cla: yes, platform-linux, needs tests)