Add dummy dart:html library for documentation.

lib/html/doc/interface/ConvolverNode.dartdoc

Index: lib/html/doc/interface/ConvolverNode.dartdoc
diff --git a/lib/html/doc/interface/ConvolverNode.dartdoc b/lib/html/doc/interface/ConvolverNode.dartdoc
new file mode 100644
index 0000000000000000000000000000000000000000..e62b392ec400b58fd7fc6dd9d08fc3a27d12a1d4
--- /dev/null
+++ b/lib/html/doc/interface/ConvolverNode.dartdoc
@@ -0,0 +1,17 @@
+// 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 ConvolverNode
+interface ConvolverNode extends AudioNode {
+
+  /** @domName ConvolverNode.buffer */
+  AudioBuffer buffer;
+
+  /** @domName ConvolverNode.normalize */
+  bool normalize;
+}