81601 Allow reuse of NavigatorObserver in Navigator.observers (framework, cla: yes, waiting for tree to go green)

81604 prototypeItem added to ReorderableList and ReorderableListView (framework, f: material design, cla: yes)

81631 Clean up some old and obsolete TODOs of mine (framework, f: material design, cla: yes, waiting for tree to go green)

81632 Be more consistent about how we mark classes that can’t be extended. (framework, cla: yes, waiting for tree to go green)

81634 Change elevation to double of MergeableMaterial (framework, f: material design, cla: yes, waiting for tree to go green)

81647 Add slider adaptive cupertino thumb color (framework, f: material design, cla: yes, f: cupertino, waiting for tree to go green)