Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/PerformanceNavigation.dartdoc

Index: lib/html/doc/interface/PerformanceNavigation.dartdoc
diff --git a/lib/html/doc/interface/PerformanceNavigation.dartdoc b/lib/html/doc/interface/PerformanceNavigation.dartdoc
deleted file mode 100644
index 7d22fab350e1c550d9d7c4659d0d9f35901a4db3..0000000000000000000000000000000000000000
--- a/lib/html/doc/interface/PerformanceNavigation.dartdoc
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright (c) 2012, 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.
-
-// WARNING:
-//   This file contains documentation that is merged into the real source.
-//   Do not make code changes here.
-
-/// @domName PerformanceNavigation
-interface PerformanceNavigation {
-
-  static final int TYPE_BACK_FORWARD = 2;
-
-  static final int TYPE_NAVIGATE = 0;
-
-  static final int TYPE_RELOAD = 1;
-
-  static final int TYPE_RESERVED = 255;
-
-  /** @domName PerformanceNavigation.redirectCount */
-  final int redirectCount;
-
-  /** @domName PerformanceNavigation.type */
-  final int type;
-}