Use ButtonCompat to get Material-y buttons in more places.

chrome/android/java/res/values-v21/styles.xml

Index: chrome/android/java/res/values-v21/styles.xml
diff --git a/chrome/android/java/res/values-v21/styles.xml b/chrome/android/java/res/values-v21/styles.xml
index 6bbefde6b0de26750f91a342e39958a0824c9eba..4035183e490ec6eb85919dac2a29ea7d1c003387 100644
--- a/chrome/android/java/res/values-v21/styles.xml
+++ b/chrome/android/java/res/values-v21/styles.xml
@@ -7,9 +7,7 @@
     <!-- Preferences -->
     <style name="PreferencesTheme" parent="ThemeWithActionBar">
         <item name="android:textColorLink">@color/pref_accent_color</item>
-        <item name="android:buttonStyle">@style/PreferenceButtonStyle</item>
         <item name="android:alertDialogTheme">@style/PreferencesDialogTheme</item>
-        <item name="android:colorButtonNormal">@color/btn_default_preferences</item>
         <item name="android:editTextBackground">@drawable/abc_edit_text_material</item>
         <item name="android:editTextStyle">@style/PreferenceEditTextStyle</item>
         <item name="android:spinnerItemStyle">@style/PreferenceSpinnerItem</item>
@@ -21,9 +19,6 @@
     <style name="PreferencesDialogTheme" parent="@android:style/Theme.Material.Light.Dialog.Alert">
         <item name="android:colorAccent">@color/pref_accent_color</item>
     </style>
-    <style name="PreferenceButtonStyle" parent="@android:style/Widget.Material.Light.Button">
-        <item name="android:textColor">#fff</item>
-    </style>
     <style name="PreferenceCategoryWithButtonStyle">
         <item name="android:paddingStart">?android:attr/listPreferredItemPaddingStart</item>
         <item name="android:paddingEnd">4dp</item>