81241 Use ColorScheme.primary (not secondary), ExpansionTile expanded color (framework, f: material design, cla: yes)

81246 Short-circuit _debugCanPerformMutations if debugDoingLayout is false (framework, cla: yes, waiting for tree to go green)

81247 Cheaper debug string for widget-provided tickers (framework, cla: yes, waiting for tree to go green)

81250 Improve performance of debugCheckHasDirectionality (framework, f: material design, cla: yes, waiting for tree to go green)

81260 Add onLongPressDown, onLongPressCancel (framework, cla: yes)

81278 Assert for valid ScrollController in Scrollbar gestures (framework, f: scrolling, cla: yes, f: cupertino, a: quality, waiting for tree to go green, a: error message)