Moved most of html lib generating scripts into tools.

sdk/lib/html/src/Device.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-part of html;
-
-/**
- * Utils for device detection.
- */
-class _Device {
-  /**
-   * Gets the browser's user agent. Using this function allows tests to inject
-   * the user agent.
-   * Returns the user agent.
-   */
-  static String get userAgent => window.navigator.userAgent;
-
-  /**
-   * Determines if the current device is running Opera.
-   */
-  static bool get isOpera => userAgent.contains("Opera", 0);
-
-  /**
-   * Determines if the current device is running Internet Explorer.
-   */
-  static bool get isIE => !isOpera && userAgent.contains("MSIE", 0);
-
-  /**
-   * Determines if the current device is running Firefox.
-   */
-  static bool get isFirefox => userAgent.contains("Firefox", 0);
-
-  /**
-   * Determines if the current device is running WebKit.
-   */
-  static bool get isWebKit => !isOpera && userAgent.contains("WebKit", 0);
-}