Add dummy dart:html library for documentation.

lib/html/doc/interface/Coordinates.dartdoc

Index: lib/html/doc/interface/Coordinates.dartdoc
diff --git a/lib/html/doc/interface/Coordinates.dartdoc b/lib/html/doc/interface/Coordinates.dartdoc
new file mode 100644
index 0000000000000000000000000000000000000000..eb9578dc1fdab344e52e6f1d6b1cf4503e986c44
--- /dev/null
+++ b/lib/html/doc/interface/Coordinates.dartdoc
@@ -0,0 +1,32 @@
+// 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 Coordinates
+interface Coordinates {
+
+  /** @domName Coordinates.accuracy */
+  final num accuracy;
+
+  /** @domName Coordinates.altitude */
+  final num altitude;
+
+  /** @domName Coordinates.altitudeAccuracy */
+  final num altitudeAccuracy;
+
+  /** @domName Coordinates.heading */
+  final num heading;
+
+  /** @domName Coordinates.latitude */
+  final num latitude;
+
+  /** @domName Coordinates.longitude */
+  final num longitude;
+
+  /** @domName Coordinates.speed */
+  final num speed;
+}