packages/SystemUI/res/layout/keyguard_user_switcher.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2014 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
  -->
<view xmlns:android="http://schemas.android.com/apk/res/android"
        class="com.android.systemui.statusbar.policy.KeyguardUserSwitcher$Container"
        android:layout_height="match_parent"
        android:layout_width="match_parent">
    <com.android.keyguard.AlphaOptimizedLinearLayout
            android:id="@+id/keyguard_user_switcher_inner"
            android:orientation="vertical"
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:layout_marginTop="@dimen/status_bar_header_height_keyguard"
            android:layout_gravity="end"
            android:gravity="end"
            android:paddingTop="4dp">
    </com.android.keyguard.AlphaOptimizedLinearLayout>
</view>