--- a/CLOBBER
+++ b/CLOBBER
@@ -12,12 +12,12 @@
 #          O               O
 #          |               |
 #          O <-- Clobber   O  <-- Clobber
 #
 # Note: The description below will be part of the error message shown to users.
 #
 # Modifying this file will now automatically clobber the buildbot machines \o/
 #
-Bug 848530 - Added a dependency file for moz.build traversal.
+Bug 872338 - Needs a clobber at least on Windows due to bug 873809
 
 Alternative to clobber is to run ./config.status from the objdir and to
 touch the CLOBBER file in the objdir.

--- a/accessible/public/moz.build
+++ b/accessible/public/moz.build
@@ -6,17 +6,16 @@
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'windows':
     DIRS += ['msaa', 'ia2']
 
 XPIDL_SOURCES += [
     'nsIAccessible.idl',
     'nsIAccessibleApplication.idl',
     'nsIAccessibleCaretMoveEvent.idl',
-    'nsIAccessibleCursorable.idl',
     'nsIAccessibleDocument.idl',
     'nsIAccessibleEditableText.idl',
     'nsIAccessibleEvent.idl',
     'nsIAccessibleHideEvent.idl',
     'nsIAccessibleHyperLink.idl',
     'nsIAccessibleHyperText.idl',
     'nsIAccessibleImage.idl',
     'nsIAccessiblePivot.idl',

deleted file mode 100644
--- a/accessible/public/nsIAccessibleCursorable.idl
+++ /dev/null
@@ -1,26 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=2 et sw=2 tw=80: */
-/* 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;
-
-/**
- * An interface implemented by an accessible object that has an associated
- * virtual cursor. Typically, a top-level application or content document.
- * A virtual cursor is an implementation of nsIAccessiblePivot that provides an
- * exclusive spot in the cursorable's subtree, this could be used to create a
- * pseudo-focus or caret browsing experience that is centered around the
- * accessibility API.
- */
-[scriptable, uuid(5452dea5-d235-496f-8757-3ca016ff49ff)]
-interface nsIAccessibleCursorable : nsISupports
-{
-  /**
-   * The virtual cursor pivot this object manages.
-   */
-  readonly attribute nsIAccessiblePivot virtualCursor;
-};

--- a/accessible/public/nsIAccessibleDocument.idl
+++ b/accessible/public/nsIAccessibleDocument.idl
@@ -1,32 +1,33 @@
 /* -*- 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 nsIAccessible;
+interface nsIAccessiblePivot;
 interface nsIDOMDocument;
 interface nsIDOMNode;
 interface nsIDOMWindow;
 
 /**
  * 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. You can also get one from 
  * nsIAccessible::GetAccessibleDocument() or 
  * nsIAccessibleEvent::GetAccessibleDocument()
  */
-[scriptable, uuid(451242bd-8a0c-4198-ae88-c053609a4e5d)]
+[scriptable, uuid(fe5b3886-2b6a-491a-80cd-a3e6342c451d)]
 interface nsIAccessibleDocument : nsISupports
 {
   /**
    * The URL of the document
    */
   readonly attribute AString URL;
 
   /**
@@ -71,12 +72,17 @@ interface nsIAccessibleDocument : nsISup
   readonly attribute nsIAccessibleDocument parentDocument;
 
   /**
    * Return the count of child document accessibles.
    */
   readonly attribute unsigned long childDocumentCount;
 
   /**
+   * The virtual cursor pivot this document manages.
+   */
+  readonly attribute nsIAccessiblePivot virtualCursor;
+
+  /**
    * Return the child document accessible at the given index.
    */
   nsIAccessibleDocument getChildDocumentAt(in unsigned long index);
 };

--- a/accessible/src/generic/DocAccessible.cpp
+++ b/accessible/src/generic/DocAccessible.cpp
@@ -125,18 +125,16 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(DocAccessible)
   NS_INTERFACE_MAP_ENTRY(nsIAccessibleDocument)
   NS_INTERFACE_MAP_ENTRY(nsIDocumentObserver)
   NS_INTERFACE_MAP_ENTRY(nsIMutationObserver)
   NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
   NS_INTERFACE_MAP_ENTRY(nsIObserver)
   NS_INTERFACE_MAP_ENTRY(nsIAccessiblePivotObserver)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIAccessibleDocument)
-  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsIAccessibleCursorable,
-                                     (mDocFlags & eCursorable))
     foundInterface = 0;
 
   nsresult status;
   if (!foundInterface) {
     // HTML document accessible must inherit from HyperTextAccessible to get
     // support text interfaces. XUL document accessible doesn't need this.
     // However at some point we may push <body> to implement the interfaces and
     // return DocAccessible to inherit from AccessibleWrap.
@@ -472,29 +470,25 @@ DocAccessible::GetChildDocumentAt(uint32
 
   if (IsDefunct())
     return NS_OK;
 
   NS_IF_ADDREF(*aDocument = GetChildDocumentAt(aIndex));
   return *aDocument ? NS_OK : NS_ERROR_INVALID_ARG;
 }
 
-// nsIAccessibleVirtualCursor method
 NS_IMETHODIMP
 DocAccessible::GetVirtualCursor(nsIAccessiblePivot** aVirtualCursor)
 {
   NS_ENSURE_ARG_POINTER(aVirtualCursor);
   *aVirtualCursor = nullptr;
 
   if (IsDefunct())
     return NS_ERROR_FAILURE;
 
-  if (!(mDocFlags & eCursorable))
-    return NS_OK;
-
   if (!mVirtualCursor) {
     mVirtualCursor = new nsAccessiblePivot(this);
     mVirtualCursor->AddObserver(this);
   }
 
   NS_ADDREF(*aVirtualCursor = mVirtualCursor);
   return NS_OK;
 }
@@ -1460,20 +1454,16 @@ DocAccessible::NotifyOfLoading(bool aIsR
 }
 
 void
 DocAccessible::DoInitialUpdate()
 {
   if (nsCoreUtils::IsTabDocument(mDocumentNode))
     mDocFlags |= eTabDocument;
 
-  // We provide a virtual cursor if this is a root doc or if it's a tab doc.
-  if (!mDocumentNode->GetParentDocument() || (mDocFlags & eTabDocument))
-    mDocFlags |= eCursorable;
-
   mLoadState |= eTreeConstructed;
 
   // The content element may be changed before the initial update and then we
   // miss the notification (since content tree change notifications are ignored
   // prior to initial update). Make sure the content element is valid.
   nsIContent* contentElm = nsCoreUtils::GetRoleContent(mDocumentNode);
   if (mContent != contentElm) {
     mContent = contentElm;

--- a/accessible/src/generic/DocAccessible.h
+++ b/accessible/src/generic/DocAccessible.h
@@ -1,17 +1,16 @@
 /* -*- 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/. */
 
 #ifndef mozilla_a11y_DocAccessible_h__
 #define mozilla_a11y_DocAccessible_h__
 
-#include "nsIAccessibleCursorable.h"
 #include "nsIAccessibleDocument.h"
 #include "nsIAccessiblePivot.h"
 
 #include "AccEvent.h"
 #include "HyperTextAccessibleWrap.h"
 
 #include "nsClassHashtable.h"
 #include "nsDataHashtable.h"
@@ -40,28 +39,25 @@ template<class Class, class Arg>
 class TNotification;
 
 class DocAccessible : public HyperTextAccessibleWrap,
                       public nsIAccessibleDocument,
                       public nsIDocumentObserver,
                       public nsIObserver,
                       public nsIScrollPositionListener,
                       public nsSupportsWeakReference,
-                      public nsIAccessibleCursorable,
                       public nsIAccessiblePivotObserver
 {
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DocAccessible, Accessible)
 
   NS_DECL_NSIACCESSIBLEDOCUMENT
 
   NS_DECL_NSIOBSERVER
 
-  NS_DECL_NSIACCESSIBLECURSORABLE
-
   NS_DECL_NSIACCESSIBLEPIVOTOBSERVER
 
 public:
 
   DocAccessible(nsIDocument* aDocument, nsIContent* aRootContent,
                 nsIPresShell* aPresShell);
   virtual ~DocAccessible();
 
@@ -487,21 +483,18 @@ protected:
 
   /**
    * State and property flags, kept by mDocFlags.
    */
   enum {
     // Whether scroll listeners were added.
     eScrollInitialized = 1 << 0,
 
-    // Whether we support nsIAccessibleCursorable.
-    eCursorable = 1 << 1,
-
     // Whether the document is a tab document.
-    eTabDocument = 1 << 2
+    eTabDocument = 1 << 1
   };
 
   /**
    * Cache of accessibles within this document accessible.
    */
   AccessibleHashtable mAccessibleCache;
   nsDataHashtable<nsPtrHashKey<const nsINode>, Accessible*>
     mNodeToAccessibleMap;
@@ -534,17 +527,17 @@ protected:
    * Keep the ARIA attribute old value that is initialized by
    * AttributeWillChange and used by AttributeChanged notifications.
    */
   nsIAtom* mARIAAttrOldValue;
 
   nsTArray<nsRefPtr<DocAccessible> > mChildDocuments;
 
   /**
-   * The virtual cursor of the document when it supports nsIAccessibleCursorable.
+   * The virtual cursor of the document.
    */
   nsRefPtr<nsAccessiblePivot> mVirtualCursor;
 
   /**
    * A storage class for pairing content with one of its relation attributes.
    */
   class AttrRelProvider
   {