Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/WebGLContextAttributes.dartdoc

Index: lib/html/doc/interface/WebGLContextAttributes.dartdoc
diff --git a/lib/html/doc/interface/WebGLContextAttributes.dartdoc b/lib/html/doc/interface/WebGLContextAttributes.dartdoc
deleted file mode 100644
index ad91298f572cfdf2a194de9fed67c6bcffb9a347..0000000000000000000000000000000000000000
--- a/lib/html/doc/interface/WebGLContextAttributes.dartdoc
+++ /dev/null
@@ -1,29 +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 WebGLContextAttributes
-interface WebGLContextAttributes {
-
-  /** @domName WebGLContextAttributes.alpha */
-  bool alpha;
-
-  /** @domName WebGLContextAttributes.antialias */
-  bool antialias;
-
-  /** @domName WebGLContextAttributes.depth */
-  bool depth;
-
-  /** @domName WebGLContextAttributes.premultipliedAlpha */
-  bool premultipliedAlpha;
-
-  /** @domName WebGLContextAttributes.preserveDrawingBuffer */
-  bool preserveDrawingBuffer;
-
-  /** @domName WebGLContextAttributes.stencil */
-  bool stencil;
-}