Fix XML tests on Safari and IE.

client/html/src/XMLElementWrappingImplementation.dart

Index: client/html/src/XMLElementWrappingImplementation.dart
diff --git a/client/html/src/XMLElementWrappingImplementation.dart b/client/html/src/XMLElementWrappingImplementation.dart
index 94aa3536961701e73ba25a98749bfc2b1dd23015..161cdbf7c5e11b4cca5ad0c6aecd4bf1d5ca0659 100644
--- a/client/html/src/XMLElementWrappingImplementation.dart
+++ b/client/html/src/XMLElementWrappingImplementation.dart
@@ -52,19 +52,25 @@ class XMLElementWrappingImplementation extends ElementWrappingImplementation
 
   String get outerHTML() {
     final container = new Element.tag("div");
-    container.elements.add(this.clone(true));
+    // Safari requires that the clone be removed from its owner document before
+    // being inserted into the HTML document.
+    container.elements.add(this.clone(true).remove());
     return container.innerHTML;
   }
 
   String get innerHTML() {
     final container = new Element.tag("div");
-    container.nodes.addAll(this.clone(true).nodes);
+    // Safari requires that the clone be removed from its owner document before
+    // being inserted into the HTML document.
+    container.nodes.addAll(this.clone(true).remove().nodes);
     return container.innerHTML;
   }
 
   void set innerHTML(String xml) {
     final xmlDoc = new XMLDocument.xml('<xml>$xml</xml>');
-    this.nodes = xmlDoc.nodes;
+    // Safari requires that the root node be removed from the document before
+    // being inserted into the HTML document.
+    this.nodes = xmlDoc.remove().nodes;
   }
 
   Node _insertAdjacentNode(String where, Node node) {