Implement document.documentElement.appendChild etc

src/wrappers/Document.js

@@ -45,6 +45,7 @@
   }
 
   [
+    'createComment',
     'createDocumentFragment',
     'createElement',
     'createElementNS',
@@ -175,6 +176,7 @@
     window.HTMLBodyElement,
     window.HTMLDocument || window.Document,  // Gecko adds these to HTMLDocument
     window.HTMLHeadElement,
+    window.HTMLHtmlElement,
   ], [
     'appendChild',
     'compareDocumentPosition',
@@ -194,6 +196,7 @@
   ], [
     'adoptNode',
     'contains',
+    'createComment',
     'createDocumentFragment',
     'createElement',
     'createElementNS',

test/js/HTMLHtmlElement.js

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2013 The Polymer Authors. All rights reserved.
+ * Use of this source code is goverened by a BSD-style
+ * license that can be found in the LICENSE file.
+ */
+
+suite('HTMLHtmlElement', function() {
+
+  var wrap = ShadowDOMPolyfill.wrap;
+
+  test('instanceof', function() {
+    var doc = wrap(document);
+    assert.instanceOf(doc.documentElement, HTMLHtmlElement);
+    assert.equal(wrap(document.documentElement), doc.documentElement);
+  });
+
+  test('appendChild', function() {
+    var doc = wrap(document);
+
+    var a = document.createComment('a');
+    var b = document.createComment('b');
+
+    document.documentElement.appendChild(a);
+    assert.equal(doc.documentElement.lastChild, a);
+
+    doc.documentElement.appendChild(b);
+    assert.equal(doc.documentElement.lastChild, b);
+  });
+
+});

test/test.main.js

@@ -59,6 +59,7 @@ var modules = [
   'HTMLContentElement.js',
   'HTMLFieldSetElement.js',
   'HTMLHeadElement.js',
+  'HTMLHtmlElement.js',
   'HTMLInputElement.js',
   'HTMLKeygenElement.js',
   'HTMLLabelElement.js',