--- a/accessible/base/DocManager.cpp
+++ b/accessible/base/DocManager.cpp
@@ -21,17 +21,16 @@
 #endif
 
 #include "mozilla/EventListenerManager.h"
 #include "mozilla/dom/Event.h" // for Event
 #include "nsContentUtils.h"
 #include "nsCURILoader.h"
 #include "nsDocShellLoadTypes.h"
 #include "nsIChannel.h"
-#include "nsIDOMDocument.h"
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsIWebNavigation.h"
 #include "nsServiceManagerUtils.h"
 #include "nsIWebProgress.h"
 #include "nsCoreUtils.h"
 #include "nsXULAppAPI.h"
 #include "mozilla/dom/TabChild.h"
 

--- a/accessible/generic/ApplicationAccessible.cpp
+++ b/accessible/generic/ApplicationAccessible.cpp
@@ -9,17 +9,16 @@
 
 #include "nsAccessibilityService.h"
 #include "nsAccUtils.h"
 #include "Relation.h"
 #include "Role.h"
 #include "States.h"
 
 #include "nsIComponentManager.h"
-#include "nsIDOMDocument.h"
 #include "nsIWindowMediator.h"
 #include "nsServiceManagerUtils.h"
 #include "mozilla/Services.h"
 #include "nsGlobalWindow.h"
 #include "nsIStringBundle.h"
 
 using namespace mozilla::a11y;
 

--- a/accessible/generic/DocAccessible.cpp
+++ b/accessible/generic/DocAccessible.cpp
@@ -18,17 +18,16 @@
 #include "RootAccessible.h"
 #include "TreeWalker.h"
 #include "xpcAccessibleDocument.h"
 
 #include "nsIMutableArray.h"
 #include "nsICommandManager.h"
 #include "nsIDocShell.h"
 #include "nsIDocument.h"
-#include "nsIDOMDocument.h"
 #include "nsPIDOMWindow.h"
 #include "nsIEditingSession.h"
 #include "nsIFrame.h"
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsImageFrame.h"
 #include "nsIPersistentProperties2.h"
 #include "nsIPresShell.h"
 #include "nsIServiceManager.h"

--- a/accessible/generic/RootAccessible.cpp
+++ b/accessible/generic/RootAccessible.cpp
@@ -3,17 +3,16 @@
  * 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/. */
 
 #include "RootAccessible.h"
 
 #include "mozilla/ArrayUtils.h"
 
 #define CreateEvent CreateEventA
-#include "nsIDOMDocument.h"
 
 #include "Accessible-inl.h"
 #include "DocAccessible-inl.h"
 #include "nsAccessibilityService.h"
 #include "nsAccUtils.h"
 #include "nsCoreUtils.h"
 #include "nsEventShell.h"
 #include "Relation.h"

--- a/accessible/interfaces/nsIAccessibleDocument.idl
+++ b/accessible/interfaces/nsIAccessibleDocument.idl
@@ -1,19 +1,20 @@
 /* -*- Mode: C++; 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/. */
 
 #include "nsISupports.idl"
 
 interface nsIAccessiblePivot;
-interface nsIDOMDocument;
 interface mozIDOMWindowProxy;
 
+webidl Document;
+
 /**
  * An interface for in-process accessibility clients
  * that wish to retrieve information about a document.
  * When accessibility is turned on in Gecko,
  * there is an nsIAccessibleDocument for each document
  * whether it is XUL, HTML or whatever.
  * You can QueryInterface to nsIAccessibleDocument from the nsIAccessible for
  * the root node of a document or you can get one from
@@ -38,19 +39,19 @@ interface nsIAccessibleDocument : nsISup
   readonly attribute AString mimeType;
 
   /**
    * The doc type of the document, as specified in the document.
    */
   readonly attribute AString docType;
 
   /**
-   * The nsIDOMDocument interface associated with this document.
+   * The Document interface associated with this document.
    */
-  readonly attribute nsIDOMDocument DOMDocument;
+  readonly attribute Document DOMDocument;
 
   /**
    * The nsIDOMWindow that the document resides in.
    */
   readonly attribute mozIDOMWindowProxy window;
 
   /**
    * Return the parent document accessible.

--- a/accessible/xpcom/xpcAccessibleDocument.cpp
+++ b/accessible/xpcom/xpcAccessibleDocument.cpp
@@ -6,17 +6,16 @@
 
 #include "xpcAccessibleDocument.h"
 #include "xpcAccessibleImage.h"
 #include "xpcAccessibleTable.h"
 #include "xpcAccessibleTableCell.h"
 
 #include "mozilla/a11y/DocAccessibleParent.h"
 #include "DocAccessible-inl.h"
-#include "nsIDOMDocument.h"
 
 using namespace mozilla;
 using namespace mozilla::a11y;
 
 ////////////////////////////////////////////////////////////////////////////////
 // nsISupports
 
 NS_IMPL_QUERY_INTERFACE_INHERITED(xpcAccessibleDocument, xpcAccessibleHyperText,
@@ -81,26 +80,26 @@ xpcAccessibleDocument::GetDocType(nsAStr
   if (!Intl())
     return NS_ERROR_FAILURE;
 
   Intl()->DocType(aType);
   return NS_OK;
 }
 
 NS_IMETHODIMP
-xpcAccessibleDocument::GetDOMDocument(nsIDOMDocument** aDOMDocument)
+xpcAccessibleDocument::GetDOMDocument(nsIDocument** aDOMDocument)
 {
   NS_ENSURE_ARG_POINTER(aDOMDocument);
   *aDOMDocument = nullptr;
 
   if (!Intl())
     return NS_ERROR_FAILURE;
 
   if (Intl()->DocumentNode())
-    CallQueryInterface(Intl()->DocumentNode(), aDOMDocument);
+    NS_ADDREF(*aDOMDocument = Intl()->DocumentNode());
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
 xpcAccessibleDocument::GetWindow(mozIDOMWindowProxy** aDOMWindow)
 {
   NS_ENSURE_ARG_POINTER(aDOMWindow);

--- a/accessible/xpcom/xpcAccessibleDocument.h
+++ b/accessible/xpcom/xpcAccessibleDocument.h
@@ -33,17 +33,17 @@ public:
 
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIAccessibleDocument
   NS_IMETHOD GetURL(nsAString& aURL) final;
   NS_IMETHOD GetTitle(nsAString& aTitle) final;
   NS_IMETHOD GetMimeType(nsAString& aType) final;
   NS_IMETHOD GetDocType(nsAString& aType) final;
-  NS_IMETHOD GetDOMDocument(nsIDOMDocument** aDOMDocument) final;
+  NS_IMETHOD GetDOMDocument(nsIDocument** aDOMDocument) final;
   NS_IMETHOD GetWindow(mozIDOMWindowProxy** aDOMWindow) final;
   NS_IMETHOD GetParentDocument(nsIAccessibleDocument** aDocument)
     final;
   NS_IMETHOD GetChildDocumentCount(uint32_t* aCount) final;
   NS_IMETHOD GetChildDocumentAt(uint32_t aIndex,
                                 nsIAccessibleDocument** aDocument)
     final;
   NS_IMETHOD GetVirtualCursor(nsIAccessiblePivot** aVirtualCursor)