anchor.diff:  class AndroidBackButtonMemoryTest {
     final String testDirectory;
     final String packageName;
  -
  -  AndroidBackButtonMemoryTest(this.testDirectory, this.packageName);
  +  final String activityName;
  +
  +  AndroidBackButtonMemoryTest(this.testDirectory, this.packageName, this.activityName);
   
     Future<TaskResult> call() {
       return inDirectory(testDirectory, () async {
  
positive.code:       for (int i = 0; i < 10; i++) {
          await device.shellExec('input', <String>['keyevent', 'KEYCODE_BACK']);
          await new Future<Null>.delayed(const Duration(milliseconds: 1000));
          final String output = await device.shellEval('am', <String>['start', '-n', 'io.flutter.examples.gallery/io.flutter.app.FlutterActivity']);
          print(output);
          if (output.contains('Error'))
            return new TaskResult.failure('unable to launch activity');
  
negative.code:   return new AndroidBackButtonMemoryTest(
      '${flutterDirectory.path}/examples/flutter_gallery',
      'io.flutter.examples.gallery',
      'io.flutter.examples.gallery.MainActivity',
    );
  }
  
  