Remove fullscreen content settings UI from Android.

chrome/android/java/res/xml/site_settings_preferences.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2015 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. -->
 
 <!-- The order of the following items is from: http://crbug.com/610358. -->
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
     <!-- All sites -->
     <org.chromium.chrome.browser.preferences.website.SiteSettingsPreference
         android:fragment="org.chromium.chrome.browser.preferences.website.SingleCategoryPreferences"
@@ skipping 25 matching lines @@
         android:fragment="org.chromium.chrome.browser.preferences.website.SingleCategoryPreferences"
         android:key="javascript" />
     <!-- Popups -->
     <org.chromium.chrome.browser.preferences.website.SiteSettingsPreference
         android:fragment="org.chromium.chrome.browser.preferences.website.SingleCategoryPreferences"
         android:key="popups" />
     <!-- Background sync -->
     <org.chromium.chrome.browser.preferences.website.SiteSettingsPreference
         android:fragment="org.chromium.chrome.browser.preferences.website.SingleCategoryPreferences"
         android:key="background_sync" />
-    <!-- Fullscreen -->
-    <org.chromium.chrome.browser.preferences.website.SiteSettingsPreference
-        android:fragment="org.chromium.chrome.browser.preferences.website.SingleCategoryPreferences"
-        android:key="fullscreen" />
     <!-- Protected content -->
     <org.chromium.chrome.browser.preferences.website.SiteSettingsPreference
         android:fragment="org.chromium.chrome.browser.preferences.website.SingleCategoryPreferences"
         android:key="protected_content" />
     <!-- Autoplay -->
     <org.chromium.chrome.browser.preferences.website.SiteSettingsPreference
         android:fragment="org.chromium.chrome.browser.preferences.website.SingleCategoryPreferences"
         android:key="autoplay" />
     <!-- Media -->
     <org.chromium.chrome.browser.preferences.website.SiteSettingsPreference
@@ skipping 14 matching lines @@
         android:key="use_storage"
         android:title="@string/website_settings_storage"
         android:icon="@drawable/settings_storage" />
     <!-- USB -->
     <org.chromium.chrome.browser.preferences.website.SiteSettingsPreference
         android:fragment="org.chromium.chrome.browser.preferences.website.UsbChooserPreferences"
         android:key="usb"
         android:title="@string/website_settings_usb"
         android:icon="@drawable/settings_usb" />
 </PreferenceScreen>