8299 Enable lambda like native callbacks in tests and add support for custom entrypoints. (cla: yes)

8308 Map glfw into third_party, and roll buildroot (cla: yes)

8309 Allow specification of std::functions as native entrypoints from Dart code. (cla: yes)

8312 Revert “Allow specification of std::functions as native entrypoints from Dart code.” (cla: yes)

8317 Android Embedding PR22: Polish - FlutterActivity Intent factories, FlutterFragment control of render modes, FlutterSurfaceView transparent until rendering is ready. (cla: yes)

8318 Reduce z-fighting on Scenic (cla: yes)

8319 Fix “PointerEvent” flow end event (cla: yes)