75604 Reland #74722 (cla: yes, f: cupertino, f: material design, framework, waiting for tree to go green)

75670 CupertinoPageTransition Optimizations (cla: yes, f: cupertino, f: material design, framework, waiting for tree to go green)

75676 Removed ButtonBar from AlertDialog (cla: yes, f: material design, framework, waiting for tree to go green)

75748 Fix constraints of popupmenu (cla: yes, f: material design, framework, waiting for tree to go green)

75761 Added scrollbar example (cla: yes, d: api docs, d: examples, documentation, f: material design, f: scrolling, framework, waiting for tree to go green)