diff --git a/accessible/windows/msaa/AccessibleWrap.cpp b/accessible/windows/msaa/AccessibleWrap.cpp
index 10e8a743da04..3f4f42354c8e 100644
--- a/accessible/windows/msaa/AccessibleWrap.cpp
+++ b/accessible/windows/msaa/AccessibleWrap.cpp
@@ -9,12 +9,14 @@
 
 #include "Compatibility.h"
 #include "DocAccessible-inl.h"
+#include "mozilla/a11y/DocAccessibleParent.h"
 #include "EnumVariant.h"
 #include "nsAccUtils.h"
 #include "nsCoreUtils.h"
 #include "nsIAccessibleEvent.h"
 #include "nsWinUtils.h"
 #include "mozilla/a11y/ProxyAccessible.h"
+#include "ProxyWrappers.h"
 #include "ServiceProvider.h"
 #include "Relation.h"
 #include "Role.h"
@@ -1274,6 +1276,22 @@ AccessibleWrap::HandleAccEvent(AccEvent* aEvent)
   return NS_OK;
 }
 
+DocProxyAccessibleWrap*
+AccessibleWrap::DocProxyWrapper() const
+{
+  MOZ_ASSERT(IsProxy());
+
+  ProxyAccessible* proxy = Proxy();
+  if (!proxy) {
+    return nullptr;
+  }
+
+  AccessibleWrap* acc = WrapperFor(proxy->Document());
+  MOZ_ASSERT(acc->IsDoc());
+
+ return static_cast<DocProxyAccessibleWrap*>(acc);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // AccessibleWrap
 
diff --git a/accessible/windows/msaa/AccessibleWrap.h b/accessible/windows/msaa/AccessibleWrap.h
index 05ce578910a3..6a1ab3abdcab 100644
--- a/accessible/windows/msaa/AccessibleWrap.h
+++ b/accessible/windows/msaa/AccessibleWrap.h
@@ -26,6 +26,7 @@
 
 namespace mozilla {
 namespace a11y {
+class DocProxyAccessibleWrap;
 
 class AccessibleWrap : public Accessible,
                        public ia2Accessible,
@@ -183,6 +184,11 @@ protected:
   uint32_t mID;
 #endif
 
+  /**
+   * Return the wrapper for the document's proxy.
+   */
+  DocProxyAccessibleWrap* DocProxyWrapper() const;
+
   /**
    * Creates ITypeInfo for LIBID_Accessibility if it's needed and returns it.
    */