chrome/android/java/res/layout/preference_spinner.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2016 The Chromium Authors. All rights reserved.
     Use of this source code is governed by a BSD-style license that can be
     found in the LICENSE file. -->

<!-- Layout used by SpinnerPreference. -->

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:chrome="http://schemas.android.com/apk/res-auto"
    style="@style/PreferenceLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <TextView
        android:id="@+id/title"
        android:layout_height="wrap_content"
        android:layout_width="match_parent" />

    <Spinner
        android:id="@+id/spinner"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:paddingStart="0dp"
        android:paddingTop="6dp"
        android:paddingBottom="4dp" />

    <View style="@style/PreferenceSpinnerUnderlineView" />

</LinearLayout>