Signal-Android/app/src/main/res/layout/fragment_media_preview_v2.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/core_grey_95"
    android:theme="@style/TextSecure.MediaPreview">

    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/toolbar_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/media_preview_bar_background"
        app:elevation="0dp">

        <View
            android:id="@+id/toolbar_cutout_spacer"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:visibility="gone" />

        <androidx.appcompat.widget.Toolbar
            android:id="@+id/toolbar"
            android:theme="?actionBarStyle"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@android:color/transparent" />

    </com.google.android.material.appbar.AppBarLayout>
    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/media_pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clickable="true"
        android:focusable="true" />
</FrameLayout>