agent/engine/default.go
func NewTaskEngine(cfg *config.Config, client dockerapi.DockerClient,
	credentialsManager credentials.Manager,
	containerChangeEventStream *eventstream.EventStream,
	imageManager ImageManager, state dockerstate.TaskEngineState,
	metadataManager containermetadata.Manager,
	resourceFields *taskresource.ResourceFields) TaskEngine {

	taskEngine := NewDockerTaskEngine(cfg, client, credentialsManager,
		containerChangeEventStream, imageManager,
		state, metadataManager, resourceFields)

	return taskEngine
}
func NewTaskEngine(cfg *config.Config, client dockerapi.DockerClient,
	credentialsManager credentials.Manager,
	containerChangeEventStream *eventstream.EventStream,
	imageManager ImageManager, state dockerstate.TaskEngineState,
	metadataManager containermetadata.Manager,
	resourceFields *taskresource.ResourceFields) TaskEngine {

	taskEngine := NewDockerTaskEngine(cfg, client, credentialsManager,
		containerChangeEventStream, imageManager,
		state, metadataManager, resourceFields)

	return taskEngine
}
// NewTaskEngine returns a default TaskEngine