Teach V8GCController how to traverse TemplateContentDocumentFragment::host

Source/bindings/scripts/code_generator_v8.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 1684 matching lines @@
     $code .= "#endif // ${conditionalString}\n" if $conditionalString;
     $code .= "\n";
     $implementation{nameSpaceInternal}->add($code);
 }
 
 sub ShouldKeepAttributeAlive
 {
     my ($interface, $attribute, $returnType) = @_;
     my $attrName = $attribute->name;
 
-    return 1 if $attribute->extendedAttributes->{"KeepAttributeAliveForGC"};
-
     # For readonly attributes (including Replaceable), as a general rule, for
     # performance reasons we keep the attribute wrapper alive while the owner
     # wrapper is alive, because the attribute never changes.
     return 0 if !IsWrapperType($returnType);
     return 0 if !IsReadonly($attribute) && !$attribute->extendedAttributes->{"Replaceable"};
 
     # However, there are a couple of exceptions.
 
     # Node lifetime is managed by object grouping.
     return 0 if InheritsInterface($interface, "Node");
@@ skipping 4572 matching lines @@
 
     return 1 if $interface->extendedAttributes->{"CustomToV8"};
     return 1 if $interface->extendedAttributes->{"SpecialWrapFor"};
     return 1 if InheritsInterface($interface, "Document");
     return 1 if SVGTypeNeedsToHoldContextElement($interface->name);
 
     return 0;
 }
 
 1;