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

Source/core/html/HTMLSelectElement.cpp

Index: Source/core/html/HTMLSelectElement.cpp
diff --git a/Source/core/html/HTMLSelectElement.cpp b/Source/core/html/HTMLSelectElement.cpp
old mode 100644
new mode 100755
index 2d581071d37568b86dd674a14514976a284ad179..c1682651de2c92da005c15a80b3b681f9f339c49
--- a/Source/core/html/HTMLSelectElement.cpp
+++ b/Source/core/html/HTMLSelectElement.cpp
@@ -1277,7 +1277,7 @@ void HTMLSelectElement::updateSelectedState(int listIndex, bool multi, bool shif
 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.
@@ -1323,7 +1323,7 @@ void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
                     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.
@@ -1332,7 +1332,9 @@ void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
         // 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;