Add font family selector ui for distilled page viewer.

chrome/android/java/res/layout/distilled_page_prefs_view.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.
 -->
 
 <org.chromium.chrome.browser.dom_distiller.DistilledPagePrefsView
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
@@ skipping 16 matching lines @@
         <RadioButton
             android:id="@+id/dark_mode"
             android:text="@string/dark_mode"
             style="@style/DistilledPagePrefThemeButton" />
         <RadioButton
             android:id="@+id/sepia_mode"
             android:text="@string/sepia_mode"
             style="@style/DistilledPagePrefThemeButton" />
 
     </RadioGroup>
+
+    <Spinner
+        android:id="@+id/font_family"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_weight="1"
+        android:orientation="horizontal"
+        android:padding="10dp"/>
+
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:orientation="horizontal"
         android:layout_marginTop="3dp">
 
         <TextView
             android:id="@+id/font_size_percentage"
             android:layout_width="wrap_content"
             android:layout_height="match_parent"
@@ skipping 23 matching lines @@
             android:layout_width="wrap_content"
             android:layout_height="match_parent"
             android:gravity="center_vertical"
             android:layout_marginEnd="3dp"
             android:textSize="20sp"
             android:text="@string/text_size_signifier" />
 
     </LinearLayout>
 
 </org.chromium.chrome.browser.dom_distiller.DistilledPagePrefsView>