Changes in webui to comply with the safe html changes. Now that Nodes can be

lib/src/emitters.dart

Index: lib/src/emitters.dart
diff --git a/lib/src/emitters.dart b/lib/src/emitters.dart
index 3fa27a94819cbc41eff4a94ab44043c56b180d3f..270ac6b518eefd8f219ee0247fbfe452ef82f4be 100644
--- a/lib/src/emitters.dart
+++ b/lib/src/emitters.dart
@@ -614,7 +614,7 @@ class WebComponentEmitter extends RecursiveEmitter {
           elemInfo.node.sourceSpan,
           "new autogenerated.DocumentFragment.html('''"
           "${escapeDartString(elemInfo.node.innerHtml, triple: true)}"
-          "''')");
+          "''', treeSanitizer: autogenerated.nullTreeSanitizer)");
       _context.printer.addLine(
           "__root.nodes.add(__shadowTemplate.clone(true));");
     }
@@ -828,30 +828,52 @@ String _emitCreateHtml(Node node, Declarations statics) {
   var isHtml = node.namespace == 'http://www.w3.org/1999/xhtml';
   var isSvg = node.namespace == 'http://www.w3.org/2000/svg';
   var isEmpty = node.attributes.length == 0 && node.nodes.length == 0;
+  var specialTags = const ['body', 'caption', 'col', 'colgroup', 'head',
+      'tbody', 'td', 'tfoot', 'th', 'thead', 'tr', 'track'];
 
-  var constructor;
+  var expr;
   // Generate precise types like "new ButtonElement()" if we can.
   if (isEmpty && isHtml) {
-    constructor = htmlElementConstructors[node.tagName];
+    var constructor = htmlElementConstructors[node.tagName];
     if (constructor != null) {
-      constructor = '$constructor()';
+      expr = 'new autogenerated.$constructor()';
     } else {
-      constructor = "Element.tag('${node.tagName}')";
+      expr = "new autogenerated.Element.tag('${node.tagName}')";
     }
   } else if (isEmpty && isSvg) {
-    constructor = "_svg.SvgElement.tag('${node.tagName}')";
-  } else {
+    expr = "new autogenerated_svg.SvgElement.tag('${node.tagName}')";
+  } else if (isSvg || !specialTags.contains(node.tagName)) {
     // TODO(sigmund): does this work for the mathml namespace?
-    var target = isSvg ? '_svg.SvgElement.svg' : 'Element.html';
-    constructor = "$target('${escapeDartString(node.outerHtml)}')";
+    var constructor = isSvg ? 'autogenerated_svg.SvgElement.svg'
+        : 'autogenerated.Element.html';
+    expr = "new $constructor("
+        "'${escapeDartString(node.outerHtml)}', "
+        "treeSanitizer: autogenerated.nullTreeSanitizer)";
+  } else {
+    expr = "autogenerated.createSafeNode('${node.tagName}',"
+        " ${_attributesAsString(node.attributes)},"
+        "'${escapeDartString(node.innerHtml)}')";
   }
-
-  var expr = 'new autogenerated.$constructor';
   var varName = '__html${statics.declarations.length}';
   statics.add('final', varName, node.sourceSpan, expr);
   return '${varName}.clone(true)';
 }
 
+String _attributesAsString(Map attributes) {
+  var sb = new StringBuffer();
+  sb.write('{');
+  bool first = true;
+  for (var key in attributes.keys) {
+    if (!first) sb.write(',');
+    first = false;
+    var sKey = escapeDartString(key);
+    var sValue = escapeDartString(attributes[key]);
+    sb.write("'$sKey': '$sValue'");
+  }
+  sb.write('}');
+  return sb.toString();
+}
+
 /** Trim down the html for the main html page. */
 void transformMainHtml(Document document, FileInfo fileInfo,
     PathMapper pathMapper, bool hasCss, bool rewriteUrls, Messages messages,