Signal-Android/res/layout/camerax_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <org.thoughtcrime.securesms.mediasend.camerax.CameraXView
        android:id="@+id/camerax_camera"
        android:layout_gravity="center"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <FrameLayout
        android:id="@+id/camerax_controls_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</FrameLayout>