Generate eventListenerCacheIndex if an EventListener is present

Source/bindings/scripts/CodeGeneratorV8.pm

 # Copyright (C) 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
 # Copyright (C) 2006 Anders Carlsson <andersca@mac.com>
 # Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
 # Copyright (C) 2006 Alexey Proskuryakov <ap@webkit.org>
 # Copyright (C) 2006 Apple Computer, Inc.
 # Copyright (C) 2007, 2008, 2009, 2012 Google Inc.
 # Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
 # Copyright (C) Research In Motion Limited 2010. All rights reserved.
 # Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
 # Copyright (C) 2012 Ericsson AB. All rights reserved.
@@ skipping 923 matching lines @@
     return toV8(impl.get(), creationContext, isolate);
 }
 
 END
 
     if (IsConstructorTemplate($interface, "Event")) {
         $header{nameSpaceWebCore}->add("bool fill${implClassName}Init(${implClassName}Init&, const Dictionary&);\n\n");
     }
 }
 
+sub HasEventListenerAttribute
+{
+    my $interface = shift;
+
+    foreach my $attribute (@{$interface->attributes}) {
+        return 1 if $attribute->type eq "EventListener";
+    }
+
+    return 0;
+}
+
 sub GetInternalFields
 {
     my $interface = shift;
 
     my @customInternalFields = ();
     # Event listeners on DOM nodes are explicitly supported in the GC controller.
     if (!InheritsInterface($interface, "Node") &&
-        InheritsExtendedAttribute($interface, "EventTarget")) {
+        (InheritsExtendedAttribute($interface, "EventTarget") || HasEventListenerAttribute($interface))) {
         push(@customInternalFields, "eventListenerCacheIndex");
     }
     return @customInternalFields;
 }
 
 sub GenerateHeaderCustomInternalFieldIndices
 {
     my $interface = shift;
     my @customInternalFields = GetInternalFields($interface);
     my $customFieldCounter = 0;
@@ skipping 5074 matching lines @@
         if ($currentInterface->extendedAttributes->{$extendedAttribute}) {
             $found = 1;
         }
         return 1 if $found;
     }, 0);
 
     return $found;
 }
 
 1;