Generate eventListenerCacheIndex if an EventListener is present

Source/bindings/scripts/CodeGeneratorV8.pm

Index: Source/bindings/scripts/CodeGeneratorV8.pm
diff --git a/Source/bindings/scripts/CodeGeneratorV8.pm b/Source/bindings/scripts/CodeGeneratorV8.pm
index eb243b6762c798c918f7e64ba1d847c8443dce84..a7c64245896e60ce3065aa08dd066b699be13ee9 100644
--- a/Source/bindings/scripts/CodeGeneratorV8.pm
+++ b/Source/bindings/scripts/CodeGeneratorV8.pm
@@ -941,6 +941,17 @@ END
     }
 }
 
+sub HasEventListenerAttribute
+{
+    my $interface = shift;
+
+    foreach my $attribute (@{$interface->attributes}) {
+        return 1 if $attribute->type eq "EventListener";
+    }
+
+    return 0;
+}
+
 sub GetInternalFields
 {
     my $interface = shift;
@@ -948,7 +959,7 @@ sub GetInternalFields
     my @customInternalFields = ();
     # Event listeners on DOM nodes are explicitly supported in the GC controller.
     if (!InheritsInterface($interface, "Node") &&
-        InheritsExtendedAttribute($interface, "EventTarget")) {
+        (InheritsExtendedAttribute($interface, "EventTarget") || HasEventListenerAttribute($interface))) {
         push(@customInternalFields, "eventListenerCacheIndex");
     }
     return @customInternalFields;