Simply part of the movement to get our docs aligned with NNBD.

* Add text to --analyze-size command output to launch DevTools with size data.

89d64daf1 Roll buildroot to flutter/buildroot@64bf32094b19bfecc2515aedb7e130f7ba15d297 (flutter/engine#23041) (#72363)

Exposes the ability to create custom Material text selection toolbar menus, and cleans up the code around these menus.

This reverts commit f8e2f074.

Small performance optimization by removing a duplicate setState call.

* Launch DevTools from pub instead of devtools_server