session-android/res/drawable/mediarail_media_outline.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >
    <corners android:radius="5dp" />

    <stroke
        android:width="3dp"
        android:color="@color/signal_primary"/>
</shape>