core/res/res/layout/notification_template_conversation_icon_container.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2021 The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License
  -->

<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/conversation_icon_container"
    android:layout_width="@dimen/conversation_content_start"
    android:layout_height="wrap_content"
    android:gravity="start|top"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:paddingTop="20dp"
    android:paddingBottom="16dp"
    android:importantForAccessibility="no"
    >

    <FrameLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:clipChildren="false"
        android:clipToPadding="false"
        android:layout_gravity="top|center_horizontal"
        >

        <!-- Big icon: 48x48, 12dp padding top, 16dp padding sides -->
        <com.android.internal.widget.CachingIconView
            android:id="@+id/conversation_icon"
            android:layout_width="@dimen/conversation_avatar_size"
            android:layout_height="@dimen/conversation_avatar_size"
            android:layout_marginLeft="@dimen/conversation_badge_protrusion"
            android:layout_marginRight="@dimen/conversation_badge_protrusion"
            android:layout_marginBottom="@dimen/conversation_badge_protrusion"
            android:scaleType="centerCrop"
            android:importantForAccessibility="no"
            />

        <ViewStub
            android:layout="@layout/conversation_face_pile_layout"
            android:layout_width="@dimen/conversation_avatar_size"
            android:layout_height="@dimen/conversation_avatar_size"
            android:layout_marginLeft="@dimen/conversation_badge_protrusion"
            android:layout_marginRight="@dimen/conversation_badge_protrusion"
            android:layout_marginBottom="@dimen/conversation_badge_protrusion"
            android:id="@+id/conversation_face_pile"
            />

        <FrameLayout
            android:id="@+id/conversation_icon_badge"
            android:layout_width="@dimen/conversation_icon_size_badged"
            android:layout_height="@dimen/conversation_icon_size_badged"
            android:layout_gravity="end|bottom"
            android:clipChildren="false"
            android:clipToPadding="false"
            >

            <com.android.internal.widget.CachingIconView
                android:id="@+id/conversation_icon_badge_bg"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_gravity="center"
                android:src="@drawable/conversation_badge_background"
                android:forceHasOverlappingRendering="false"
                android:scaleType="center"
                />

            <com.android.internal.widget.CachingIconView
                android:id="@+id/icon"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_margin="4dp"
                android:layout_gravity="center"
                android:forceHasOverlappingRendering="false"
                />

            <com.android.internal.widget.CachingIconView
                android:id="@+id/conversation_icon_badge_ring"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:src="@drawable/conversation_badge_ring"
                android:visibility="gone"
                android:forceHasOverlappingRendering="false"
                android:clipToPadding="false"
                android:scaleType="center"
                />
        </FrameLayout>
    </FrameLayout>
</FrameLayout>