ce61eda70c
## Background
The Windows runner has a race at startup:
1. **Platform thread**: creates a hidden window
2. **Platform thread**: launches the Flutter engine
3. **UI/Raster threads**: renders the first frame
4. **Platform thread**: Registers a callback to show the window once the next frame has been rendered.
Steps 3 and 4 happen in parallel and it is possible for step 3 to complete before step 4 starts. In this scenario, the next frame callback is never called and the window is never shown.
As a result the `windows_startup_test`'s test, which [verifies that the "show window" callback is called](1f09a8662d/dev/integration_tests/windows_startup_test/windows/runner/flutter_window.cpp (L60-L64)), can flake if the first frame is rendered before the show window callback has been registered.
## Solution
This change makes the runner schedule a frame after it registers the next frame callback. If step 3 hasn't completed yet, this no-ops as a frame is already scheduled. If step 3 has already completed, a new frame will be rendered, which will call the next frame callback and show the window.
Part of https://github.com/flutter/flutter/issues/119415
See this thread for alternatives that were considered: https://github.com/flutter/engine/pull/42061#issuecomment-1550080722
Example of embedding Flutter using FlutterView
This project demonstrates how to embed Flutter within an iOS or Android application. On iOS, the iOS and Flutter components are built with Xcode. On Android, the Android and Flutter components are built with Android Studio or Gradle.
You can read more about accessing platform and third-party services in Flutter.
iOS
You can open ios/Runner.xcworkspace in Xcode and build the project as
usual.
Android
You can open android/ in Android Studio and build the project as usual.