Remove support for the externalResourcesRequired attribute.

Source/core/svg/SVGFilterElement.h

Index: Source/core/svg/SVGFilterElement.h
diff --git a/Source/core/svg/SVGFilterElement.h b/Source/core/svg/SVGFilterElement.h
index f929a3e0b2e9fec3d87a703ef4dde1f16b5c56cb..733887b8081b67bee5d951662f01d0b60d0592ad 100644
--- a/Source/core/svg/SVGFilterElement.h
+++ b/Source/core/svg/SVGFilterElement.h
@@ -29,15 +29,13 @@
 #include "core/svg/SVGAnimatedInteger.h"
 #include "core/svg/SVGAnimatedLength.h"
 #include "core/svg/SVGElement.h"
-#include "core/svg/SVGExternalResourcesRequired.h"
 #include "core/svg/SVGURIReference.h"
 #include "core/svg/SVGUnitTypes.h"
 
 namespace WebCore {
 
 class SVGFilterElement FINAL : public SVGElement,
-                               public SVGURIReference,
-                               public SVGExternalResourcesRequired {
+                               public SVGURIReference {
 public:
     static PassRefPtr<SVGFilterElement> create(const QualifiedName&, Document&);
 
@@ -73,7 +71,6 @@ private:
         DECLARE_ANIMATED_INTEGER(FilterResX, filterResX)
         DECLARE_ANIMATED_INTEGER(FilterResY, filterResY)
         DECLARE_ANIMATED_STRING(Href, href)
-        DECLARE_ANIMATED_BOOLEAN(ExternalResourcesRequired, externalResourcesRequired)
     END_DECLARE_ANIMATED_PROPERTIES
 
     HashSet<RefPtr<Node> > m_clientsToAdd;