move polymer.dart into dart svn

pkg/polymer/lib/safe_html.dart

+// Copyright (c) 2011, 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(sigmund): move this library to a shared package? or make part of
+// dart:html?
+library polymer.safe_html;
+
+/** Declares a string that is a well-formed HTML fragment. */
+class SafeHtml {
+
+  /** Underlying html string. */
+  final String _html;
+
+  // TODO(sigmund): provide a constructor that does html validation
+  SafeHtml.unsafe(this._html);
+
+  String toString() => _html;
+
+  operator ==(other) => other is SafeHtml && _html == other._html;
+  int get hashCode => _html.hashCode;
+}
+
+/**
+ * Declares a string that is safe to use in a Uri attribute, such as `<a href=`,
+ * to avoid cross-site scripting (XSS) attacks.
+ */
+class SafeUri {
+  final String _uri;
+
+  // TODO(sigmund): provide a constructor that takes or creates a Uri and
+  // validates that it is safe (not a javascript: scheme, for example)
+  SafeUri.unsafe(this._uri);
+
+  String toString() => _uri;
+
+  operator ==(other) => other is SafeUri && _uri == other._uri;
+  int get hashCode => _uri.hashCode;
+}