packages/SystemUI/res/layout/remote_input.xml

<?xml version="1.0" encoding="utf-8"?>

<!--
  ~ Copyright (C) 2015 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 -->
<com.android.systemui.statusbar.policy.RemoteInputView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:theme="@style/systemui_theme_light"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:paddingStart="4dp"
        android:paddingEnd="2dp"
        android:paddingBottom="4dp"
        android:paddingTop="2dp">

    <view class="com.android.systemui.statusbar.policy.RemoteInputView$RemoteEditText"
            android:id="@+id/remote_input_text"
            android:layout_height="wrap_content"
            android:layout_width="match_parent"
            android:singleLine="true"
            android:imeOptions="actionSend" />

    <ProgressBar
            android:id="@+id/remote_input_progress"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom"
            android:visibility="invisible"
            android:indeterminate="true"
            style="?android:attr/progressBarStyleHorizontal" />

</com.android.systemui.statusbar.policy.RemoteInputView>