Use native radiobutton for Default Search Engine picker dialog.

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

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2015 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. -->
 
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:background="?android:attr/selectableItemBackground"
     android:gravity="center_vertical"
     android:orientation="horizontal"
     android:paddingTop="6dp"
     android:paddingBottom="6dp">
 
-    <RadioButton
+    <android.widget.RadioButton
         android:id="@+id/radiobutton"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="21dp"
         android:layout_marginEnd="16dp"
-        android:background="@null"
         android:clickable="false" />
 
     <LinearLayout
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_weight="1"
         android:orientation="vertical">
         <TextView
             android:id="@+id/description"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:textSize="17sp" />
         <TextView
             android:id="@+id/link"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginEnd="21dp" />
     </LinearLayout>
 
 </LinearLayout>