Popup open and hide using Alt+KeyDown

Source/web/PopupListBox.cpp

 /*
  * Copyright (c) 2011, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 225 matching lines @@
         adjustSelectedIndex(m_items.size());
         break;
     default:
         if (!event.ctrlKey() && !event.altKey() && !event.metaKey()
             && isPrintableChar(event.windowsVirtualKeyCode())
             && isCharacterTypeEvent(event))
             typeAheadFind(event);
         break;
     }
 
+    if (event.altKey() && (event.keyIdentifier() == "Down" || event.keyIdentifier() == "Up")) {
+        hidePopup();
+        return true;
+    }
+
     if (m_originalIndex != m_selectedIndex) {
         // Keyboard events should update the selection immediately (but we don't
         // want to fire the onchange event until the popup is closed, to match
         // IE). We change the original index so we revert to that when the
         // popup is closed.
         m_acceptedIndexOnAbandon = m_selectedIndex;
 
         setOriginalIndex(m_selectedIndex);
         m_popupClient->setTextFromItem(m_selectedIndex);
     }
@@ skipping 563 matching lines @@
 {
     return numItems() && IntRect(0, 0, width(), height()).contains(point);
 }
 
 int PopupListBox::popupContentHeight() const
 {
     return height();
 }
 
 } // namespace blink