title: Android Chrome custom tabs fade in animation
body: <p>I have an app with a Chrome custom tab. I can get enter and exit animations working with the builder as long as they are transitions (enter/exit from left/right):</p>
  
  <pre><code>.setStartAnimations(mContext, R.anim.enter_from_right, R.anim.exit_to_left)
  .setExitAnimations(mContext, R.anim.enter_from_left, R.anim.exit_to_right)
  </code></pre>
  
  <p>As soon as I try and have a fade in/out animation with alpha it doesn't work. I get a black screen and have to kill the app from multitasking. Animation XML fade in:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;set xmlns:android="http://schemas.android.com/apk/res/android"
  android:interpolator="@android:interpolator/linear"
  &gt;
  &lt;alpha
      android:fromAlpha="0.0"
      android:toAlpha="1.0"
      android:duration="500"
      android:fillAfter="true"
      /&gt;
  &lt;/set&gt;
  </code></pre>
  
  <p>fade out:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;set xmlns:android="http://schemas.android.com/apk/res/android"
  android:interpolator="@android:interpolator/linear"
  &gt;
  &lt;alpha
      android:fromAlpha="1.0"
      android:toAlpha="0.0"
      android:duration="500"
      android:fillAfter="true"
      /&gt;
  &lt;/set&gt;
  </code></pre>
  
  <p>I have tried changing the interpolator and fill after/before but it doesn't seem to make a difference.</p>