f4ac622197
Similar to https://github.com/flutter/engine/pull/41733 and https://github.com/flutter/engine/pull/41782, this causes the macos embedding to wait until it hears that the scheduler binding has registered itself before proceeding to send termination requests to the framework. This allows applications that don't use the framework (just use `dart:ui` directly) to exit automatically when the last window is closed. Without this change, the last window closes, but the app does not exit. Depends on framework PR https://github.com/flutter/flutter/pull/126075 landing first.