move polymer.dart into dart svn

pkg/polymer/lib/src/html5_utils.dart

+// 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.
+
+// TODO(jmesserly): html5lib might be a better home for this.
+// But at the moment we only need it here.
+
+library html5_utils;
+
+/**
+ * HTML attributes that expect a URL value.
+ * <http://dev.w3.org/html5/spec/section-index.html#attributes-1>
+ *
+ * Every one of these attributes is a URL in every context where it is used in
+ * the DOM. The comments show every DOM element where an attribute can be used.
+ */
+const urlAttributes = const [
+  'action',     // in form
+  'background', // in body
+  'cite',       // in blockquote, del, ins, q
+  'data',       // in object
+  'formaction', // in button, input
+  'href',       // in a, area, link, base, command
+  'icon',       // in command
+  'manifest',   // in html
+  'poster',     // in video
+  'src',        // in audio, embed, iframe, img, input, script, source, track,
+                //    video
+];