Docs: Deleting the rest of the preview/ directory due to N Release migration

This directory no longer has a reason to exist since we've migrated all
of its contents to their respective homes.

Change-Id: I604b5104a04b0f627b9e0a9971215bf37755dbd5
diff --git a/docs/html/preview/_book.yaml b/docs/html/preview/_book.yaml
deleted file mode 100644
index a3458dd..0000000
--- a/docs/html/preview/_book.yaml
+++ /dev/null
@@ -1,323 +0,0 @@
-toc:
-- title: Program Overview
-  path: /preview/overview.html
-  path_attributes:
-  - name: es-lang
-    value: Información general del programa
-  - name: in-lang
-    value: Ikhtisar Program
-  - name: ja-lang
-    value: プログラム概要
-  - name: ko-lang
-    value: 프로그램 개요
-  - name: pt-br-lang
-    value: Visão geral do programa
-  - name: ru-lang
-    value: Обзор программы
-  - name: vi-lang
-    value: Tổng quan về Chương trình
-  - name: zh-cn-lang
-    value: 计划概览
-  - name: zh-tw-lang
-    value: 程式總覽
-
-- title: Support and Release Notes
-  path: /preview/support.html
-
-- title: Set Up the Preview
-  path: /preview/setup-sdk.html
-  path_attributes:
-  - name: es-lang
-    value: Configurar el SDK de la versión preliminar
-  - name: in-lang
-    value: Menyiapkan Preview
-  - name: ja-lang
-    value: Preview SDK のセットアップ
-  - name: ko-lang
-    value: 미리 보기 SDK 설정하기
-  - name: pt-br-lang
-    value: Configuração do Preview SDK
-  - name: ru-lang
-    value: Настройка пакета SDK Preview
-  - name: vi-lang
-    value: Kiểm thử trên Thiết bị
-  - name: zh-cn-lang
-    value: 设置预览版 SDK
-  - name: zh-tw-lang
-    value: 設定預覽版 SDK
-
-- title: Test on a Device
-  path: /preview/download.html
-  path_attributes:
-  - name: es-lang
-    value: Pruebe en un dispositivo
-  - name: in-lang
-    value: Menguji pada Perangkat
-  - name: ja-lang
-    value: デバイス上でテストする
-  - name: ko-lang
-    value: 기기에서 테스트
-  - name: pt-br-lang
-    value: Testar em um dispositivo
-  - name: ru-lang
-    value: Тестирование на устройстве
-  - name: vi-lang
-    value: Kiểm thử trên Thiết bị
-  - name: zh-cn-lang
-    value: 在设备上测试
-  - name: zh-tw-lang
-    value: 在裝置上測試
-
-- title: Behavior Changes
-  path: /preview/behavior-changes.html
-  path_attributes:
-  - name: es-lang
-    value: Cambios en los comportamientos
-  - name: in-lang
-    value: Perubahan Perilaku
-  - name: ja-lang
-    value: 動作の変更点
-  - name: ko-lang
-    value: 동작 변경
-  - name: pt-br-lang
-    value: Mudanças de comportamento
-  - name: ru-lang
-    value: Изменения в работе
-  - name: vi-lang
-    value: Các thay đổi Hành vi
-  - name: zh-cn-lang
-    value: 行为变更
-  - name: zh-tw-lang
-    value: 行為變更
-  section:
-  - title: Background Optimizations
-    path: /preview/features/background-optimization.html
-    path_attributes:
-    - name: es-lang
-      value: Optimizaciones en segundo plano
-    - name: in-lang
-      value: Optimisasi Latar Belakang
-    - name: ja-lang
-      value: バックグラウンド処理の最適化
-    - name: ko-lang
-      value: 백그라운드 최적화
-    - name: pt-br-lang
-      value: Otimizações em segundo plano
-    - name: ru-lang
-      value: Оптимизация фоновых процессов
-    - name: vi-lang
-      value: Tối ưu hóa Chạy ngầm
-    - name: zh-cn-lang
-      value: 后台优化
-    - name: zh-tw-lang
-      value: 背景最佳化
-  - title: Language and Locale
-    path: /preview/features/multilingual-support.html
-    path_attributes:
-    - name: es-lang
-      value: Idioma y configuración regional
-    - name: in-lang
-      value: Bahasa dan Lokal
-    - name: ja-lang
-      value: 言語とロケール
-    - name: ko-lang
-      value: 언어 및 로케일
-    - name: pt-br-lang
-      value: Idioma e localidade
-    - name: ru-lang
-      value: Язык и языковой стандарт
-    - name: vi-lang
-      value: Ngôn ngữ và Bản địa
-    - name: zh-cn-lang
-      value: 语言和区域设置
-    - name: zh-tw-lang
-      value: 語言和地區設定
-
-- title: Android N for Developers
-  path: /preview/api-overview.html
-  path_attributes:
-  - name: es-lang
-    value: Información general de la API
-  - name: in-lang
-    value: Android N untuk Pengembang
-  - name: ja-lang
-    value: API の概要
-  - name: ko-lang
-    value: API 개요
-  - name: pt-br-lang
-    value: Visão geral da API
-  - name: ru-lang
-    value: Обзор API-интерфейсов
-  - name: vi-lang
-    value: Android N cho Nhà phát triển
-  - name: zh-cn-lang
-    value: API 概览
-  - name: zh-tw-lang
-    value: API 總覽
-  section:
-  - title: Multi-Window Support
-    path: /preview/features/multi-window.html
-    path_attributes:
-    - name: es-lang
-      value: Compatibilidad con ventanas múltiples
-    - name: in-lang
-      value: Dukungan Multi-Jendela
-    - name: ja-lang
-      value: マルチ ウィンドウのサポート
-    - name: ko-lang
-      value: 다중 창 지원
-    - name: pt-br-lang
-      value: Suporte a várias janelas
-    - name: ru-lang
-      value: Поддержка многооконного режима
-    - name: vi-lang
-      value: Hỗ trợ đa cửa sổ
-    - name: zh-cn-lang
-      value: 多窗口支持
-    - name: zh-tw-lang
-      value: 多視窗支援
-  - title: Notifications
-    path: /preview/features/notification-updates.html
-    path_attributes:
-    - name: es-lang
-      value: Notificaciones
-    - name: in-lang
-      value: Pemberitahuan
-    - name: ja-lang
-      value: 通知
-    - name: ko-lang
-      value: 알림
-    - name: pt-br-lang
-      value: Notificações
-    - name: ru-lang
-      value: Уведомления
-    - name: vi-lang
-      value: Thông báo
-    - name: zh-cn-lang
-      value: 通知
-    - name: zh-tw-lang
-      value: 通知
-  - title: Data Saver
-    path: /preview/features/data-saver.html
-  - title: TV Recording
-    path: /preview/features/tv-recording-api.html
-    path_attributes:
-    - name: es-lang
-      value: Grabación de TV
-    - name: in-lang
-      value: Perekaman TV
-    - name: ja-lang
-      value: TV の録画
-    - name: ko-lang
-      value: TV 녹화
-    - name: pt-br-lang
-      value: Gravação para TV
-    - name: ru-lang
-      value: Запись ТВ
-    - name: vi-lang
-      value: Ghi lại TV
-    - name: zh-cn-lang
-      value: TV 录制
-    - name: zh-tw-lang
-      value: 電視錄製
-  - title: Key Attestation
-    path: /preview/features/key-attestation.html
-  - title: Network Security Configuration
-    path: /preview/features/security-config.html
-    path_attributes:
-    - name: es-lang
-      value: Configuración de seguridad de la red
-    - name: ja-lang
-      value: ネットワーク セキュリティ構成
-    - name: ko-lang
-      value: 네트워크 보안 구성
-    - name: pt-br-lang
-      value: Configurações de segurança de rede
-    - name: ru-lang
-      value: Конфигурация сетевой безопасности
-    - name: vi-lang
-      value: Cấu hình Bảo mật mạng
-    - name: zh-cn-lang
-      value: 网络安全配置
-    - name: zh-tw-lang
-      value: 網路安全性設定
-  - title: ICU4J Support
-    path: /preview/features/icu4j-framework.html
-    path_attributes:
-    - name: es-lang
-      value: API de ICU4J del framework de Android
-    - name: in-lang
-      value: ICU4J Android Framework API
-    - name: ja-lang
-      value: ICU4J Android フレームワーク API
-    - name: ko-lang
-      value: ICU4J Android 프레임워크 API
-    - name: pt-br-lang
-      value: APIs de estrutura do Android para ICU4J
-    - name: ru-lang
-      value: API-интерфейсы ICU4J в платформе Android
-    - name: vi-lang
-      value: API Khuôn khổ Android ICU4J
-    - name: zh-cn-lang
-      value: ICU4J Android 框架 API
-    - name: zh-tw-lang
-      value: ICU4J Android 架構 API
-  - title: Android for Work Updates
-    path: /preview/features/afw.html
-  - title: Scoped Directory Access
-    path: /preview/features/scoped-folder-access.html
-    path_attributes:
-    - name: es-lang
-      value: Acceso a directorios determinados
-    - name: ja-lang
-      value: 特定のディレクトリへのアクセス
-    - name: ko-lang
-      value: 범위가 지정된 디렉터리 액세스
-    - name: pt-br-lang
-      value: Acesso a diretórios com escopo
-    - name: ru-lang
-      value: Доступ к выделенным каталогам
-    - name: vi-lang
-      value: Truy cập Thư mục theo Phạm vi
-    - name: zh-cn-lang
-      value: 作用域目录访问
-    - name: zh-tw-lang
-      value: 限定範圍目錄存取
-
-- title: Samples
-  path: /preview/samples.html
-  path_attributes:
-  - name: es-lang
-    value: Ejemplos
-  - name: in-lang
-    value: Contoh
-  - name: ja-lang
-    value: サンプル
-  - name: ko-lang
-    value: 샘플
-  - name: pt-br-lang
-    value: Exemplos
-  - name: ru-lang
-    value: Примеры
-  - name: zh-cn-lang
-    value: 示例
-  - name: zh-tw-lang
-    value: 範例
-
-- title: License Agreement
-  path: /preview/license.html
-  path_attributes:
-  - name: es-lang
-    value: Contrato de licencia
-  - name: ja-lang
-    value: 使用許諾契約
-  - name: ko-lang
-    value: 라이선스 계약
-  - name: pt-br-lang
-    value: Contrato de licença
-  - name: ru-lang
-    value: Лицензионное соглашение
-  - name: zh-cn-lang
-    value: 许可协议
-  - name: zh-tw-lang
-    value: 授權協議
diff --git a/docs/html/preview/_project.yaml b/docs/html/preview/_project.yaml
deleted file mode 100644
index 3ec851a..0000000
--- a/docs/html/preview/_project.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
-name: "Preview"
-home_url: /preview/
-description: "Android N final SDK is now available."
-content_license: cc3-apache2
-buganizer_id: 30209417