Add ButtonCompat: a Material-styled button on all versions of Android.

chrome/android/java/res/values-v17/styles.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.
 -->
 
 <resources>
     <!-- Preferences -->
     <style name="PreferencesTheme" parent="ThemeWithActionBar">
         <item name="android:textColorLink">@color/pref_accent_color</item>
@@ skipping 166 matching lines @@
     </style>
     <style name="info_bubble">
         <item name="android:textColor">@android:color/white</item>
         <item name="android:textStyle">bold</item>
         <item name="android:textSize">18sp</item>
     </style>
     <style name="FullscreenNotificationBubble" parent="@android:style/Animation.Toast">
         <item name="android:windowEnterAnimation">@anim/fullscreen_notification_in</item>
     </style>
 
+    <!-- Buttons -->
+    <style name="ButtonCompatBase">
+        <item name="android:minWidth">88dp</item>
+        <item name="android:minHeight">36dp</item>
+        <item name="android:textSize">14sp</item>
+        <item name="android:paddingStart">20dp</item>
+        <item name="android:paddingEnd">20dp</item>
+        <item name="android:paddingTop">5dp</item>
+        <item name="android:paddingBottom">5dp</item>
+        <item name="android:textAllCaps">true</item>
+        <item name="android:focusable">true</item>
+        <item name="android:clickable">true</item>
+        <item name="android:gravity">center_vertical|center_horizontal</item>
+    </style>
+    <style name="ButtonCompat" parent="ButtonCompatBase">
+        <item name="android:background">@drawable/button_compat_shape</item>
+    </style>
+    <style name="ButtonBorderlessCompat" parent="ButtonCompat">
+        <item name="android:background">?attr/selectableItemBackground</item>
+    </style>
+
 </resources>