title: MotionLayout not rendered when set the Scene
body: <p>have a nice day</p>
  <p>I try to create Motion layout programmatically by extending it. Just add view to it and invoke the motion.</p>
  <p>However, when i try to <code>setScene(...)</code> my layout is blank like no render process is happen.
  Maybe i missing something?</p>
  <p>Here is the code:</p>
  <pre><code>class SimpleMotionLayout @JvmOverloads constructor(
      context: Context,
      attrs: AttributeSet? = null,
      defStyleAttr: Int = 0
  ) : MotionLayout(context, attrs, defStyleAttr) {
  
      private var _simpleTransition: MotionScene.Transition? = null
      val simpleTransition: MotionScene.Transition?
          get() = _simpleTransition
  
      init {
          initDefaultConstraint(this)
          setDebugMode(DEBUG_SHOW_PATH and DEBUG_SHOW_PROGRESS)
  
          val motionScene = MotionScene(this)
          _simpleTransition = createTransition(motionScene)
  
          /**
           * The order matters here.
           * [MotionScene.addTransition] adds the transition to the scene while
           * [MotionScene.setTransition] sets the transition to be the current transition.
           */
          motionScene.addTransition(_simpleTransition)
          motionScene.setTransition(_simpleTransition)
  
          scene = motionScene
      }
  
      private fun initDefaultConstraint(motionLayout: ConstraintLayout) {
          // View
          val squareView = View(context).apply {
              id = R.id.default_button
              setBackgroundColor(Color.BLACK)
          }
          motionLayout.addView(
              squareView,
              LayoutParams(
                  fromDp(context, 52),
                  fromDp(context, 52)
              )
          )
  
          val set = ConstraintSet()
          set.clone(motionLayout)
  
          // Setup constraint set to TOP, LEFT to the Parent
          set.connect(
              squareView.id,
              TOP,
              PARENT_ID,
              TOP
          )
          set.connect(
              squareView.id,
              START,
              PARENT_ID,
              START
          )
  
          set.applyTo(motionLayout)
      }
  }
  </code></pre>
  <p>When i remove the <code>scene = motionScene</code> line, the view is successfully appeared.</p>
  <p><a href="https://i.stack.imgur.com/ClgeF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ClgeF.png" alt="enter image description here" /></a></p>
  <p>Thank you</p>