session-android/res/layout/verify_scan_fragment.xml

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

    <org.thoughtcrime.securesms.components.camera.CameraView
            android:id="@+id/scanner"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:camera="0"/>

    <LinearLayout android:id="@+id/overlay"
                  android:layout_width="match_parent"
                  android:layout_height="match_parent"
                  android:orientation="vertical">

        <org.thoughtcrime.securesms.components.ShapeScrim
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                app:radius="0.3"
                app:shape="circle"/>


    </LinearLayout>

</FrameLayout>