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
  -->

<!-- LinearLayout -->
<com.android.systemui.statusbar.policy.RemoteInputView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:theme="@style/systemui_theme_remote_input"
        android:id="@+id/remote_input"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:paddingEnd="12dp">

    <view class="com.android.systemui.statusbar.policy.RemoteInputView$RemoteEditText"
            android:id="@+id/remote_input_text"
            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:paddingTop="2dp"
            android:paddingBottom="4dp"
            android:paddingStart="16dp"
            android:paddingEnd="12dp"
            android:gravity="start|center_vertical"
            android:textAppearance="?android:attr/textAppearance"
            android:textColor="@color/remote_input_text"
            android:textColorHint="@color/remote_input_hint"
            android:textSize="16sp"
            android:background="@null"
            android:singleLine="true"
            android:ellipsize="start"
            android:imeOptions="actionSend" />

    <FrameLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:paddingTop="2dp"
            android:paddingBottom="4dp">

        <ImageButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:paddingStart="12dp"
                android:paddingEnd="12dp"
                android:paddingTop="12dp"
                android:paddingBottom="12dp"
                android:id="@+id/remote_input_send"
                android:src="@drawable/ic_send"
                android:tint="@color/remote_input_send"
                android:tintMode="src_in"
                android:background="@drawable/ripple_drawable" />

        <ProgressBar
                android:id="@+id/remote_input_progress"
                android:layout_width="24dp"
                android:layout_height="24dp"
                android:layout_gravity="center"
                android:visibility="invisible"
                android:indeterminate="true"
                style="?android:attr/progressBarStyleSmall" />

    </FrameLayout>

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