12469 Started asserting the FlutterEngine is running before communicating over channels. (cla: yes)

12470 [web_ui] Check if a pointer is already down for the specific device (cla: yes)

12479 Refactoring text_editing.dart (cla: yes)

12563 Remove use of the blobs snapshot format from unittests (cla: yes)

12565 Remove references to topaz (cla: yes)

12572 Update linux toolchain for fuchsia (cla: yes)

12573 [flutter_runner] Refactor thread_application pair to ActiveApplication (cla: yes)

12578 Revert “Update linux toolchain for fuchsia” (cla: yes)

12587 Split out the logic to handle status bar touches into its own function (cla: yes)