Remove support for the externalResourcesRequired attribute.

Source/core/svg/SVGPolyElement.h

Index: Source/core/svg/SVGPolyElement.h
diff --git a/Source/core/svg/SVGPolyElement.h b/Source/core/svg/SVGPolyElement.h
index 4cc460158dfc1e6a97f6d8aad047385024c4818f..f0c6b47457a10f47708dcee2cad042deb2f5b023 100644
--- a/Source/core/svg/SVGPolyElement.h
+++ b/Source/core/svg/SVGPolyElement.h
@@ -23,14 +23,12 @@
 
 #include "SVGNames.h"
 #include "core/svg/SVGAnimatedBoolean.h"
-#include "core/svg/SVGExternalResourcesRequired.h"
 #include "core/svg/SVGGeometryElement.h"
 #include "core/svg/SVGPointList.h"
 
 namespace WebCore {
 
-class SVGPolyElement : public SVGGeometryElement
-                     , public SVGExternalResourcesRequired {
+class SVGPolyElement : public SVGGeometryElement {
 public:
     SVGListPropertyTearOff<SVGPointList>* points();
     SVGListPropertyTearOff<SVGPointList>* animatedPoints();
@@ -60,7 +58,6 @@ private:
 
 private:
     BEGIN_DECLARE_ANIMATED_PROPERTIES(SVGPolyElement)
-        DECLARE_ANIMATED_BOOLEAN(ExternalResourcesRequired, externalResourcesRequired)
     END_DECLARE_ANIMATED_PROPERTIES
 };