Avoid referencing an HTMLMediaElement if is currently being deleted

Source/core/dom/GenericEventQueue.cpp

Index: Source/core/dom/GenericEventQueue.cpp
diff --git a/Source/core/dom/GenericEventQueue.cpp b/Source/core/dom/GenericEventQueue.cpp
index 172074f0071ee69f41a5d15c4e776ef306a0b0ea..9644a76c9b65bc596cc4bf097beb482af2eb4905 100644
--- a/Source/core/dom/GenericEventQueue.cpp
+++ b/Source/core/dom/GenericEventQueue.cpp
@@ -100,6 +100,21 @@ void GenericEventQueue::close()
     m_pendingEvents.clear();
 }
 
+bool GenericEventQueue::enqueueEventWithoutTarget(PassRefPtr<Event> event)
+{
+    if (m_isClosed)
+        return false;
+
+    ASSERT(!event->target());
+
+    m_pendingEvents.append(event);
+
+    if (!m_timer.isActive())
+        m_timer.startOneShot(0);
+
+    return true;
+}
+
 void GenericEventQueue::cancelAllEvents()
 {
     m_timer.stop();