ion-guide">the
     migration guide</a> for more details, including a script to help with the migration.</div>
</div>
<div class="block">A rating for media content. The style of a rating can be one of <a href="HeartRating.html" title="class in com.google.android.exoplayer2"><code>HeartRating</code></a>, <a href="PercentageRating.html" title="class in com.google.android.exoplayer2"><code>PercentageRating</code></a>, <a href="StarRating.html" title="class in com.google.android.exoplayer2"><code>StarRating</co