Add KeyName and KeyLocation to frog dom.

client/dom/src/KeyLocation.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.
+
+/**
+ * Defines the standard key locations returned by
+ * KeyboardEvent.getKeyLocation.
+ */
+interface KeyLocation {
+
+  /**
+   * The event key is not distinguished as the left or right version
+   * of the key, and did not originate from the numeric keypad (or did not
+   * originate with a virtual key corresponding to the numeric keypad).
+   */
+  static final int STANDARD = 0;
+
+  /**
+   * The event key is in the left key location.
+   */
+  static final int LEFT = 1;
+
+  /**
+   * The event key is in the right key location.
+   */
+  static final int RIGHT = 2;
+
+  /**
+   * The event key originated on the numeric keypad or with a virtual key
+   * corresponding to the numeric keypad.
+   */
+  static final int NUMPAD = 3;
+
+  /**
+   * The event key originated on a mobile device, either on a physical
+   * keypad or a virtual keyboard.
+   */
+  static final int MOBILE = 4;
+
+  /**
+   * The event key originated on a game controller or a joystick on a mobile
+   * device.
+   */
+  static final int JOYSTICK = 5;
+}