diff -r 000000000000 -r 6474c204b198 accessible/src/base/EventQueue.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/accessible/src/base/EventQueue.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,88 @@
+/* -*- 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_EventQueue_h_
+#define mozilla_a11y_EventQueue_h_
+
+#include "AccEvent.h"
+
+namespace mozilla {
+namespace a11y {
+
+class DocAccessible;
+
+/**
+ * Used to organize and coalesce pending events.
+ */
+class EventQueue
+{
+protected:
+  EventQueue(DocAccessible* aDocument) : mDocument(aDocument) { }
+
+  /**
+   * Put an accessible event into the queue to process it later.
+   */
+  bool PushEvent(AccEvent* aEvent);
+
+  /**
+   * Process events from the queue and fires events.
+   */
+  void ProcessEventQueue();
+
+private:
+  EventQueue(const EventQueue&) MOZ_DELETE;
+  EventQueue& operator = (const EventQueue&) MOZ_DELETE;
+
+  // Event queue processing
+  /**
+   * Coalesce redundant events from the queue.
+   */
+  void CoalesceEvents();
+
+  /**
+   * Coalesce events from the same subtree.
+   */
+  void CoalesceReorderEvents(AccEvent* aTailEvent);
+
+  /**
+   * Coalesce two selection change events within the same select control.
+   */
+  void CoalesceSelChangeEvents(AccSelChangeEvent* aTailEvent,
+                               AccSelChangeEvent* aThisEvent,
+                               uint32_t aThisIndex);
+
+  /**
+   * Coalesce text change events caused by sibling hide events.
+   */
+  void CoalesceTextChangeEventsFor(AccHideEvent* aTailEvent,
+                                   AccHideEvent* aThisEvent);
+  void CoalesceTextChangeEventsFor(AccShowEvent* aTailEvent,
+                                   AccShowEvent* aThisEvent);
+
+  /**
+    * Create text change event caused by hide or show event. When a node is
+    * hidden/removed or shown/appended, the text in an ancestor hyper text will
+    * lose or get new characters.
+    */
+   void CreateTextChangeEventFor(AccMutationEvent* aEvent);
+
+protected:
+
+  /**
+   * The document accessible reference owning this queue.
+   */
+  DocAccessible* mDocument;
+
+  /**
+   * Pending events array. Don't make this an nsAutoTArray; we use
+   * SwapElements() on it.
+   */
+  nsTArray<nsRefPtr<AccEvent> > mEvents;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif // mozilla_a11y_EventQueue_h_