Add chat list widget with translucent gradient

activity_main.xml

...    
<com.pierfrancescosoffritti.androidyoutubeplayer.core.player.views.YouTubePlayerView ... />
    
    <!-- Translucent gradient overlay background to make chat more visible -->
    <View
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:background="@drawable/bg_chat"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="@+id/messagesList" />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/messagesList"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_marginBottom="@dimen/margin_x_small"
        android:orientation="vertical"
        android:overScrollMode="never"
        android:paddingLeft="@dimen/margin_small"
        android:paddingRight="@dimen/margin_small"
        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
        app:layout_constraintBottom_toTopOf="@+id/sendMessageButton"
        app:layout_constraintHeight_percent="0.35" />
...