diff --git a/custom-elements/adopted-callback.html b/custom-elements/adopted-callback.html
index 5c08a04a4210d7..1ed4634dba9ff8 100644
--- a/custom-elements/adopted-callback.html
+++ b/custom-elements/adopted-callback.html
@@ -117,6 +117,38 @@
         });
     }, 'Moving the shadow host of a custom element from the owner document into ' + documentName + ' must enqueue and invoke adoptedCallback');
 
+    promise_test(function () {
+        return getDocument().then(function (doc) {
+            const instance = document.createElement('my-custom-element');
+            const host = document.createElement('div');
+            const shadowRoot = host.attachShadow({mode: 'closed'});
+            shadowRoot.appendChild(instance);
+            document.body.appendChild(host);
+
+            calls = [];
+            doc.documentElement.appendChild(shadowRoot);
+            assert_array_equals(calls, ['disconnected', 'adopted', document, doc, 'connected']);
+        });
+    }, 'Moving the shadow host\'s shadow of a custom element from the owner document into ' + documentName + ' must enqueue and invoke adoptedCallback');
+
+    promise_test(function () {
+        return getDocument().then(function (doc) {
+            const instance = document.createElement('my-custom-element');
+            const template = document.createElement('template');
+            const templateContent = template.content;
+            templateContent.appendChild(instance);
+            document.body.appendChild(template);
+
+            calls = [];
+            doc.documentElement.appendChild(templateContent);
+            if (doc === templateContent.ownerDocument) {
+                assert_array_equals(calls, ['connected']);
+            } else {
+                assert_array_equals(calls, ['adopted', templateContent.ownerDocument, doc, 'connected']);
+            }
+        });
+    }, 'Moving the <template>\'s content of a custom element from the owner document into ' + documentName + ' must enqueue and invoke adoptedCallback');
+
     promise_test(function () {
         return getDocument().then(function (doc) {
             var instance = document.createElement('my-custom-element');
diff --git a/dom/nodes/adoption.window.js b/dom/nodes/adoption.window.js
new file mode 100644
index 00000000000000..86893a4ae770e4
--- /dev/null
+++ b/dom/nodes/adoption.window.js
@@ -0,0 +1,58 @@
+// Testing DocumentFragment with host separately as it has a different node document by design
+test(() => {
+  const df = document.createElement("template").content;
+  const child = df.appendChild(new Text('hi'));
+  assert_not_equals(df.ownerDocument, document);
+  const nodeDocument = df.ownerDocument;
+  document.body.appendChild(df);
+  assert_equals(df.childNodes.length, 0);
+  assert_equals(child.ownerDocument, document);
+  assert_equals(df.ownerDocument, nodeDocument);
+}, `appendChild() and DocumentFragment with host`);
+
+test(() => {
+  const df = document.createElement("template").content;
+  const child = df.appendChild(new Text('hi'));
+  const nodeDocument = df.ownerDocument;
+  document.adoptNode(df);
+  assert_equals(df.childNodes.length, 1);
+  assert_equals(child.ownerDocument, nodeDocument);
+  assert_equals(df.ownerDocument, nodeDocument);
+}, `adoptNode() and DocumentFragment with host`);
+
+[
+  {
+    "name": "DocumentFragment",
+    "creator": doc => doc.createDocumentFragment()
+  },
+  {
+    "name": "ShadowRoot",
+    "creator": doc => doc.createElementNS("http://www.w3.org/1999/xhtml", "div").attachShadow({mode: "closed"})
+  }
+].forEach(dfTest => {
+  test(() => {
+    const doc = new Document();
+    const df = dfTest.creator(doc);
+    const child = df.appendChild(new Text('hi'));
+    assert_equals(df.ownerDocument, doc);
+
+    document.body.appendChild(df);
+    assert_equals(df.childNodes.length, 0);
+    assert_equals(child.ownerDocument, document);
+    assert_equals(df.ownerDocument, doc);
+  }, `appendChild() and ${dfTest.name}`);
+
+  test(() => {
+    const doc = new Document();
+    const df = dfTest.creator(doc);
+    const child = df.appendChild(new Text('hi'));
+    if (dfTest.name === "ShadowRoot") {
+      assert_throws("HierarchyRequestError", () => document.adoptNode(df));
+    } else {
+      document.adoptNode(df);
+      assert_equals(df.childNodes.length, 1);
+      assert_equals(child.ownerDocument, document);
+      assert_equals(df.ownerDocument, document);
+    }
+  }, `adoptNode() and ${dfTest.name}`);
+});
diff --git a/html/semantics/scripting-1/the-template-element/template-element/template-content-hierarcy.html b/html/semantics/scripting-1/the-template-element/template-element/template-content-hierarcy.html
index 1f33b96b342c4a..046395ac7c728a 100644
--- a/html/semantics/scripting-1/the-template-element/template-element/template-content-hierarcy.html
+++ b/html/semantics/scripting-1/the-template-element/template-element/template-content-hierarcy.html
@@ -1,19 +1,11 @@
 <!DOCTYPE html>
-<html>
-<head>
-<title></title>
-</head>
 <meta name="author" title="Takayoshi Kochi" href="mailto:kochi@chromium.org">
-<meta name="assert" title="host-including inclusive ancestor should be checked for template content">
-<link rel="help" href="https://dom.spec.whatwg.org/#concept-tree-host-including-inclusive-ancestor">
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-</head>
-<body>
+<div id=log></div>
 <div id="parent">
   <template id="tmpl"><span>Happy Templating!</span></template>
 </div>
-</body>
 <script>
 test(() => {
   var parent = document.getElementById('parent');
@@ -53,12 +45,11 @@
   assert_not_equals(new_doc, tmpl_doc);
 
   // Try moving tmpl.content to new_doc and check the results.
-  var new_node = new_doc.adoptNode(tmpl.content);
-  assert_equals(new_node.ownerDocument, new_doc);
+  const tmplContentNodeDocument = tmpl.content.ownerDocument;
+  const tmplContentAdoptResult = new_doc.adoptNode(tmpl.content);
+  assert_equals(tmpl.content, tmplContentAdoptResult);
   assert_equals(tmpl.ownerDocument, document);
-  assert_equals(tmpl.content.ownerDocument, new_doc);
-  assert_not_equals(tmpl.content.ownerDocument, tmpl_doc);
-  assert_not_equals(tmpl.content.ownerDocument, document);
+  assert_equals(tmpl.content.ownerDocument, tmplContentNodeDocument);
 
   // Hierarchy checks at various combinations.
   assert_throws('HierarchyRequestError', () => {
@@ -79,7 +70,7 @@
   assert_equals(tmpl.content.firstChild, span,
                 '<span> should be kept until it is removed, even after ' +
                 'adopted to another document.');
-  new_doc.body.appendChild(new_node);
+  new_doc.body.appendChild(tmpl.content);
   assert_equals(tmpl.content.firstChild, null,
                 '<span> should be removed from template content.');
   assert_equals(tmpl_content_reference, tmpl.content,
@@ -88,4 +79,3 @@
 }, 'Template content should throw exception when its ancestor in ' +
    'a different document but connected via host is being append.');
 </script>
-</html>