67946 Migrate Scaffold SnackBars in the framework to ScaffoldMessenger (a: tests, cla: yes, d: api docs, d: examples, documentation, f: material design, framework, team, waiting for tree to go green)

67947 Deprecate old SnackBar methods (cla: yes, f: material design, framework, severe: API break, severe: new feature, waiting for tree to go green)

67952 Replace obsolete FlatButton reference in flutter_driver extension_test.dart (a: tests, cla: yes, framework)

67969 Revert “Pass RouteSettings to the internal Route in showCupertinoModalPopup” (cla: yes, f: cupertino, framework)

67988 prevent pageView scrolling when calling ensureVisible (cla: yes, framework, waiting for tree to go green)