Remove stale files from lib/html/src.

lib/html/src/CloseEvent.dart

Index: lib/html/src/CloseEvent.dart
diff --git a/lib/html/src/CloseEvent.dart b/lib/html/src/CloseEvent.dart
deleted file mode 100644
index 124ab6dc9a864461aa48fe126003584d741175c6..0000000000000000000000000000000000000000
--- a/lib/html/src/CloseEvent.dart
+++ /dev/null
@@ -1,15 +0,0 @@
-// 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.
-
-interface CloseEvent extends Event default CloseEventWrappingImplementation {
-
-  CloseEvent(String type, int code, String reason,
-      [bool canBubble, bool cancelable, bool wasClean]);
-
-  int get code();
-
-  String get reason();
-
-  bool get wasClean();
-}