Follow system LTR/RTL direction in billing address spinner.

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

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2014 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. -->
 
 <!-- EditText views in FloatLabelLayout require both hint and contentDescription to be set
      to work correctly for accessibility because FloatLabelLayout sometimes clear hint. -->
 <!--suppress ContentDescription -->
 <merge
     xmlns:android="http://schemas.android.com/apk/res/android"
@@ skipping 44 matching lines @@
         android:baselineAligned="false"
         android:layout_marginStart="@dimen/pref_autofill_field_horizontal_padding"
         android:layout_marginEnd="@dimen/pref_autofill_field_horizontal_padding" >
 
         <LinearLayout
             android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:orientation="vertical"
             android:paddingEnd="10dp" >
-            <Spinner
+            <android.support.v7.widget.AppCompatSpinner
                 android:id="@+id/autofill_credit_card_editor_month_spinner"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content" />
             <View style="@style/PreferenceSpinnerUnderlineView" />
         </LinearLayout>
 
        <LinearLayout
             android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:orientation="vertical" >
-              <Spinner
+              <android.support.v7.widget.AppCompatSpinner
                   android:id="@+id/autofill_credit_card_editor_year_spinner"
                   android:layout_width="match_parent"
                   android:layout_height="wrap_content" />
               <View style="@style/PreferenceSpinnerUnderlineView"  />
         </LinearLayout>
     </LinearLayout>
 
     <TextView
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:focusable="true"
         android:paddingTop="@dimen/pref_autofill_field_top_padding"
         android:textAppearance="@style/PreferenceFloatLabelTextAppearance"
         android:text="@string/autofill_credit_card_editor_billing_address"
         android:paddingStart="@dimen/pref_autofill_field_horizontal_padding"
         android:paddingEnd="@dimen/pref_autofill_field_horizontal_padding" />
 
-    <Spinner
+    <android.support.v7.widget.AppCompatSpinner
         android:id="@+id/autofill_credit_card_editor_billing_address_spinner"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:paddingTop="@dimen/pref_autofill_field_top_padding"
         android:paddingStart="@dimen/pref_autofill_field_horizontal_padding"
-        android:paddingEnd="@dimen/pref_autofill_field_horizontal_padding" />
+        android:paddingEnd="@dimen/pref_autofill_field_horizontal_padding"
+        android:textDirection="locale" />
     <View style="@style/PreferenceSpinnerUnderlineView"
         android:paddingStart="@dimen/pref_autofill_field_horizontal_padding"
         android:paddingEnd="@dimen/pref_autofill_field_horizontal_padding" />
 
 </merge>