50976 serve the generated main.dart file so source_maps work for it (cla: yes, tool, waiting for tree to go green)

50978 nit: Add a short comment explain path dependencies (cla: yes, tool, waiting for customer response)

50979 Colored box and container optimization (a: tests, cla: yes, f: material design, framework, perf: speed, severe: API break, severe: performance)

50980 Upgrade dartdoc to 0.30.1 (cla: yes, team)

50981 [versions] update to latest web driver (cla: yes, team, waiting for tree to go green)

50984 Revert “Animated placeholder perf” (cla: yes, team)

50985 Enable TextStyle hash test on the Web (a: tests, a: typography, cla: yes, framework, waiting for tree to go green)