Add support for DOM Level 3 WheelEvent

Source/core/dom/EventTarget.cpp

Index: Source/core/dom/EventTarget.cpp
diff --git a/Source/core/dom/EventTarget.cpp b/Source/core/dom/EventTarget.cpp
index db4032152b38c8c78206f0b42599858ce018126c..48315742d557c8419737ff727a77b944c0bcf4f9 100644
--- a/Source/core/dom/EventTarget.cpp
+++ b/Source/core/dom/EventTarget.cpp
@@ -181,6 +181,9 @@ static AtomicString prefixedType(const Event* event)
     if (event->type() == eventNames().transitionendEvent)
         return eventNames().webkitTransitionEndEvent;
 
+    if (event->type() == eventNames().wheelEvent)
+        return eventNames().mousewheelEvent;
+
     return emptyString();
 }
 
@@ -209,7 +212,7 @@ bool EventTarget::fireEventListeners(Event* event)
         event->setType(unprefixedTypeName);
     }
 
-    if (!prefixedTypeName.isEmpty()) {
+    if (prefixedTypeName == eventNames().webkitTransitionEndEvent) {
         if (DOMWindow* executingWindow = this->executingWindow()) {
             if (listenerPrefixedVector) {
                 if (listenerUnprefixedVector)