diff --git a/dom/webidl/Document.webidl b/dom/webidl/Document.webidl
index ba2ec17ea..26985202b 100644
--- a/dom/webidl/Document.webidl
+++ b/dom/webidl/Document.webidl
@@ -136,7 +136,6 @@ partial interface Document {
   // user interaction
   [Pure]
   readonly attribute WindowProxy? defaultView;
-  readonly attribute Element? activeElement;
   [Throws]
   boolean hasFocus();
   //(HTML only)         attribute DOMString designMode;
@@ -283,8 +282,6 @@ partial interface Document {
 
 // http://dev.w3.org/csswg/cssom/#extensions-to-the-document-interface
 partial interface Document {
-    [Constant]
-    readonly attribute StyleSheetList styleSheets;
     attribute DOMString? selectedStyleSheetSet;
     readonly attribute DOMString? lastStyleSheetSet;
     readonly attribute DOMString? preferredStyleSheetSet;
@@ -456,3 +453,4 @@ Document implements ParentNode;
 Document implements OnErrorEventHandlerForNodes;
 Document implements GeometryUtils;
 Document implements FontFaceSource;
+Document implements DocumentOrShadowRoot;
diff --git a/dom/webidl/DocumentOrShadowRoot.webidl b/dom/webidl/DocumentOrShadowRoot.webidl
new file mode 100644
index 000000000..16388d126
--- /dev/null
+++ b/dom/webidl/DocumentOrShadowRoot.webidl
@@ -0,0 +1,29 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * https://dom.spec.whatwg.org/#documentorshadowroot
+ * http://w3c.github.io/webcomponents/spec/shadow/#extensions-to-the-documentorshadowroot-mixin
+ */
+
+[NoInterfaceObject]
+interface DocumentOrShadowRoot {
+  // Not implemented yet: bug 1430308.
+  // Selection? getSelection();
+  // Not implemented yet: bug 1430301.
+  // Element? elementFromPoint (float x, float y);
+  // Not implemented yet: bug 1430301.
+  // sequence<Element> elementsFromPoint (float x, float y);
+  // Not implemented yet: bug 1430307.
+  // CaretPosition? caretPositionFromPoint (float x, float y);
+
+  readonly attribute Element? activeElement;
+  readonly attribute StyleSheetList styleSheets;
+
+  // Not implemented yet: bug 1430303.
+  // readonly attribute Element? pointerLockElement;
+  // Not implemented yet: bug 1430305.
+  // readonly attribute Element? fullscreenElement;
+};
diff --git a/dom/webidl/ShadowRoot.webidl b/dom/webidl/ShadowRoot.webidl
index 81b50e58b..83acd4161 100644
--- a/dom/webidl/ShadowRoot.webidl
+++ b/dom/webidl/ShadowRoot.webidl
@@ -20,8 +20,6 @@ enum ShadowRootMode {
 [Func="nsDocument::IsWebComponentsEnabled"]
 interface ShadowRoot : DocumentFragment
 {
-  readonly attribute Element? activeElement;
-
   // Shadow DOM v1
   readonly attribute ShadowRootMode mode;
   readonly attribute Element host;
@@ -34,6 +32,5 @@ interface ShadowRoot : DocumentFragment
   [CEReactions, SetterThrows, TreatNullAs=EmptyString]
   attribute DOMString innerHTML;
   attribute boolean applyAuthorStyles;
-  readonly attribute StyleSheetList styleSheets;
 };
 
diff --git a/dom/webidl/moz.build b/dom/webidl/moz.build
index 4dd7fae95..11e3925bc 100644
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -113,6 +113,7 @@ WEBIDL_FILES = [
     'Directory.webidl',
     'Document.webidl',
     'DocumentFragment.webidl',
+    'DocumentOrShadowRoot.webidl',
     'DocumentTimeline.webidl',
     'DocumentType.webidl',
     'DOMCursor.webidl',