resolverによる解決

gistfile1.txt

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Playables;

[System.Serializable]
public class TextUpdateAsset : PlayableAsset
{
	public override PlayableHandle CreatePlayable (PlayableGraph graph, GameObject go)
	{
		var handle = graph.CreateScriptPlayable<TextUpdatePlayable> ();
		bool result;
		handle.GetObject<TextUpdatePlayable> ().text = (UnityEngine.UI.Text)graph.resolver.GetReferenceValue ("title", out result);
		return handle;
	}
}

SetResolver.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Playables;
using UnityEngine.UI;

public class SetResolve : MonoBehaviour
{
	[SerializeField] PlayableDirector playableDirector;
	[SerializeField] Text label;

	void Start ()
	{
		playableDirector.SetReferenceValue ("title", label);
	}
}