OnChange event should fire if the multiple selection changes in listbox using mouse

Source/core/html/HTMLSelectElement.cpp

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
@@ skipping 1259 matching lines @@
     if (m_activeSelectionAnchorIndex < 0 || !shiftSelect)
         setActiveSelectionAnchorIndex(listIndex);
 
     setActiveSelectionEndIndex(listIndex);
     updateListBoxSelection(!multiSelect);
 }
 
 void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
 {
     const Vector<HTMLElement*>& listItems = this->listItems();
-
+    bool dragSelection = false;

[Inactive, 2014/04/20 00:43:41]

I don't understand how the changes to this file could have any effect..

     if (event->type() == EventTypeNames::mousedown && event->isMouseEvent() && toMouseEvent(event)->button() == LeftButton) {
         focus();
         // Calling focus() may cause us to lose our renderer, in which case do not want to handle the event.
         if (!renderer())
             return;
 
         // Convert to coords relative to the list box if needed.
         MouseEvent* mouseEvent = toMouseEvent(event);
         IntPoint localOffset = roundedIntPoint(renderer()->absoluteToLocal(mouseEvent->absoluteLocation(), UseTransforms));
         int listIndex = toRenderListBox(renderer())->listIndexAtOffset(toIntSize(localOffset));
@@ skipping 25 matching lines @@
                         return;
 
                     setActiveSelectionEndIndex(listIndex);
                     updateListBoxSelection(false);
                 } else {
                     setActiveSelectionAnchorIndex(listIndex);
                     setActiveSelectionEndIndex(listIndex);
                     updateListBoxSelection(true);
                 }
             }
-            event->setDefaultHandled();
+            dragSelection = true;

[Inactive, 2014/04/20 00:43:41]

The clang static analyzer (rightfully) complains about this assignment being
useless since dragSelection is never used later.

         }
     } else if (event->type() == EventTypeNames::mouseup && event->isMouseEvent() && toMouseEvent(event)->button() == LeftButton && renderer() && !toRenderBox(renderer())->autoscrollInProgress()) {
         // We didn't start this click/drag on any options.
         if (m_lastOnChangeSelection.isEmpty())
             return;
         // This makes sure we fire dispatchFormControlChangeEvent for a single
         // click. For drag selection, onChange will fire when the autoscroll
         // timer stops.
-        listBoxOnChange();
+        if (!dragSelection) {

[Inactive, 2014/04/20 00:43:41]

dragSelection will always be false here since it is set to true in an "else if"
scope.

+            listBoxOnChange();
+        }
     } else if (event->type() == EventTypeNames::keydown) {
         if (!event->isKeyboardEvent())
             return;
         const String& keyIdentifier = toKeyboardEvent(event)->keyIdentifier();
 
         bool handled = false;
         int endIndex = 0;
         if (m_activeSelectionEndIndex < 0) {
             // Initialize the end index
             if (keyIdentifier == "Down" || keyIdentifier == "PageDown") {
@@ skipping 230 matching lines @@
     remove(index);
     return true;
 }
 
 bool HTMLSelectElement::isInteractiveContent() const
 {
     return true;
 }
 
 } // namespace