diff -r 000000000000 -r 6474c204b198 accessible/src/windows/msaa/HyperTextAccessibleWrap.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/accessible/src/windows/msaa/HyperTextAccessibleWrap.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,102 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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 "HyperTextAccessibleWrap.h"
+#include "Accessible-inl.h"
+
+#include "nsEventShell.h"
+
+#include "mozilla/StaticPtr.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+StaticRefPtr<Accessible> HyperTextAccessibleWrap::sLastTextChangeAcc;
+StaticAutoPtr<nsString> HyperTextAccessibleWrap::sLastTextChangeString;
+uint32_t HyperTextAccessibleWrap::sLastTextChangeStart = 0;
+uint32_t HyperTextAccessibleWrap::sLastTextChangeEnd = 0;
+bool HyperTextAccessibleWrap::sLastTextChangeWasInsert = false;
+
+NS_IMPL_ISUPPORTS_INHERITED0(HyperTextAccessibleWrap,
+                             HyperTextAccessible)
+
+STDMETHODIMP
+HyperTextAccessibleWrap::QueryInterface(REFIID aIID, void** aInstancePtr)
+{
+  if (!aInstancePtr)
+    return E_FAIL;
+
+  *aInstancePtr = nullptr;
+
+  if (IsTextRole()) {
+    if (aIID == IID_IAccessibleText)
+      *aInstancePtr =
+        static_cast<IAccessibleText*>(static_cast<ia2AccessibleText*>(this));
+    else if (aIID == IID_IAccessibleHypertext)
+      *aInstancePtr = static_cast<IAccessibleHypertext*>(this);
+    else if (aIID == IID_IAccessibleEditableText)
+      *aInstancePtr = static_cast<IAccessibleEditableText*>(this);
+
+    if (*aInstancePtr) {
+      AddRef();
+      return S_OK;
+    }
+  }
+
+  return AccessibleWrap::QueryInterface(aIID, aInstancePtr);
+}
+
+nsresult
+HyperTextAccessibleWrap::HandleAccEvent(AccEvent* aEvent)
+{
+  uint32_t eventType = aEvent->GetEventType();
+
+  if (eventType == nsIAccessibleEvent::EVENT_TEXT_REMOVED ||
+      eventType == nsIAccessibleEvent::EVENT_TEXT_INSERTED) {
+    Accessible* accessible = aEvent->GetAccessible();
+    if (accessible && accessible->IsHyperText()) {
+      sLastTextChangeAcc = accessible;
+      if (!sLastTextChangeString)
+        sLastTextChangeString = new nsString();
+
+      AccTextChangeEvent* event = downcast_accEvent(aEvent);
+      event->GetModifiedText(*sLastTextChangeString);
+      sLastTextChangeStart = event->GetStartOffset();
+      sLastTextChangeEnd = sLastTextChangeStart + event->GetLength();
+      sLastTextChangeWasInsert = event->IsTextInserted();
+    }
+  }
+
+  return HyperTextAccessible::HandleAccEvent(aEvent);
+}
+
+nsresult
+HyperTextAccessibleWrap::GetModifiedText(bool aGetInsertedText,
+                                         nsAString& aText,
+                                         uint32_t* aStartOffset,
+                                         uint32_t* aEndOffset)
+{
+  aText.Truncate();
+  *aStartOffset = 0;
+  *aEndOffset = 0;
+
+  if (!sLastTextChangeAcc)
+    return NS_OK;
+
+  if (aGetInsertedText != sLastTextChangeWasInsert)
+    return NS_OK;
+
+  if (sLastTextChangeAcc != this)
+    return NS_OK;
+
+  *aStartOffset = sLastTextChangeStart;
+  *aEndOffset = sLastTextChangeEnd;
+  aText.Append(*sLastTextChangeString);
+
+  return NS_OK;
+}
+