Add dummy dart:html library for documentation.

lib/html/doc/interface/OESVertexArrayObject.dartdoc

+// 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 OESVertexArrayObject
+interface OESVertexArrayObject {
+
+  static final int VERTEX_ARRAY_BINDING_OES = 0x85B5;
+
+  /** @domName OESVertexArrayObject.bindVertexArrayOES */
+  void bindVertexArrayOES(WebGLVertexArrayObjectOES arrayObject);
+
+  /** @domName OESVertexArrayObject.createVertexArrayOES */
+  WebGLVertexArrayObjectOES createVertexArrayOES();
+
+  /** @domName OESVertexArrayObject.deleteVertexArrayOES */
+  void deleteVertexArrayOES(WebGLVertexArrayObjectOES arrayObject);
+
+  /** @domName OESVertexArrayObject.isVertexArrayOES */
+  bool isVertexArrayOES(WebGLVertexArrayObjectOES arrayObject);
+}