54640 Allow WIllPopCallback to return null or false to veto the pop. (cla: yes, f: material design, framework, waiting for tree to go green)

54674 Add searchFieldStyle (cla: yes, f: material design, framework, waiting for tree to go green)

54706 Wire in focusNode, focusColor, autofocus, and dropdownColor to DropdownButtonFormField (cla: yes, f: material design, framework, waiting for tree to go green)

54714 [Material] Added BottomNavigationBarTheme (cla: yes, f: material design, framework, waiting for tree to go green)

54902 Paste shows only when content on clipboard (a: text input, cla: yes, f: cupertino, f: material design, framework, waiting for tree to go green)