Notifications custom layouts: make the buttons look good in Material.

chrome/android/java/res/values-v21/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>
         <item name="android:alertDialogTheme">@style/PreferencesDialogTheme</item>
@@ skipping 60 matching lines @@
     <style name="WebNotificationOrigin"
         parent="@android:style/TextAppearance.Material.Notification.Info"/>
     <style name="WebNotificationTime"
         parent="@android:style/TextAppearance.Material.Notification.Time"/>
     <style name="WebNotificationDivider">
         <!-- From the non-public Drawable notification_template_divider -->
         <item name="android:background">#29000000</item>
     </style>
     <style name="WebNotificationButton"
         parent="@android:style/Widget.DeviceDefault.Light.Button.Borderless.Small">
-        <!-- From the non-public Color secondary_text_default_material_light -->
-        <item name="android:textColor">#8a000000</item>
+        <item name="android:textColor">@color/secondary_text_default_material_light</item>
+        <item name="android:background">@drawable/web_notification_button_background</item>
     </style>
 
     <style name="IncognitoTheme" parent="MainTheme">
         <item name="android:colorPrimary">@color/incognito_primary_color</item>
     </style>
 
     <!-- Theme variation for low-end devices.
 
         Since ChromeActivities are not HW accelerated, they don't get fancy
         material shadows for popups. This theme sets drawable with pre-baked
@@ skipping 18 matching lines @@
         <item name="android:popupWindowStyle">@style/ListPopupWindow.LowEnd</item>
         <item name="android:listPopupWindowStyle">@style/ListPopupWindow.LowEnd</item>
         <item name="android:spinnerStyle">@style/Spinner.LowEnd</item>
         <item name="android:autoCompleteTextViewStyle">@style/AutoCompleteTextView.LowEnd</item>
 
         <!-- Without HW acceleration the default text cursor looks weird (top
              half is way brighter than the bottom), so we use our own. -->
         <item name="android:textCursorDrawable">@drawable/text_cursor_lowend</item>
     </style>
 </resources>