Implement app update orchestration (T-402)

app-win7/platform/windows/platform_windows.go

@@ -3,11 +3,13 @@
 package windows
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"os/exec"
 	"path/filepath"
 	"strings"
+	"time"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
@@ -49,6 +51,12 @@ func (platform) IsRunning(_ string, entrypoint string) (bool, error) {
 	})
 }
 
+func (target platform) WaitForExit(ctx context.Context, appID, entrypoint string, timeout time.Duration) error {
+	return waitForExit(ctx, timeout, func() (bool, error) {
+		return target.IsRunning(appID, entrypoint)
+	}, systemExitWaitClock{})
+}
+
 func (platform) Start(command launch.Command) (int, error) {
 	if !filepath.IsAbs(command.Entrypoint) || !filepath.IsAbs(command.WorkingDirectory) {
 		return 0, fmt.Errorf("launch command must contain absolute paths")