packages/SystemUI/res/layout/qs_media_panel_options.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2019 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
  -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/qs_media_controls_options"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:gravity="center"
    android:layout_gravity="center"
    android:padding="10dp"
    >
    <ImageButton
        android:id="@+id/remove"
        android:layout_width="48dp"
        android:layout_height="48dp"
        android:src="@android:drawable/ic_menu_delete"
        android:padding="8dp"
    />
    <ImageButton
        android:id="@+id/cancel"
        android:layout_width="48dp"
        android:layout_height="48dp"
        android:src="@android:drawable/ic_menu_revert"
        android:padding="8dp"
    />
</LinearLayout>