Introduce toSVGViewElement(), and refactor setupInitialView() using it

Source/core/svg/SVGViewElement.h

Index: Source/core/svg/SVGViewElement.h
diff --git a/Source/core/svg/SVGViewElement.h b/Source/core/svg/SVGViewElement.h
index d2bf387c7ae0fe40389efe8dae468284ef31fd18..deaaf732a9700fadd17a1f68b3ca698dd255aa0d 100644
--- a/Source/core/svg/SVGViewElement.h
+++ b/Source/core/svg/SVGViewElement.h
@@ -21,6 +21,7 @@
 #ifndef SVGViewElement_h
 #define SVGViewElement_h
 
+#include "SVGNames.h"
 #include "core/svg/SVGAnimatedBoolean.h"
 #include "core/svg/SVGAnimatedPreserveAspectRatio.h"
 #include "core/svg/SVGAnimatedRect.h"
@@ -65,6 +66,12 @@ private:
     SVGStringList m_viewTarget;
 };
 
+inline SVGViewElement* toSVGViewElement(Node* node)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->hasTagName(SVGNames::viewTag));
+    return static_cast<SVGViewElement*>(node);
+}
+
 } // namespace WebCore
 
 #endif