Introduce toSVGAnimateElement(), and use it

Source/core/svg/SVGAnimateElement.cpp

 /*
  * Copyright (C) 2004, 2005 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 93 matching lines @@
 
     ASSERT(percentage >= 0 && percentage <= 1);
     ASSERT(m_animatedPropertyType != AnimatedTransformList || hasTagName(SVGNames::animateTransformTag));
     ASSERT(m_animatedPropertyType != AnimatedUnknown);
     ASSERT(m_animator);
     ASSERT(m_animator->type() == m_animatedPropertyType);
     ASSERT(m_fromType);
     ASSERT(m_fromType->type() == m_animatedPropertyType);
     ASSERT(m_toType);
 
-    ASSERT(resultElement->hasTagName(SVGNames::animateTag)
-        || resultElement->hasTagName(SVGNames::animateColorTag)
-        || resultElement->hasTagName(SVGNames::animateTransformTag)
-        || resultElement->hasTagName(SVGNames::setTag));
-
-    SVGAnimateElement* resultAnimationElement = static_cast<SVGAnimateElement*>(resultElement);
+    SVGAnimateElement* resultAnimationElement = toSVGAnimateElement(resultElement);
     ASSERT(resultAnimationElement->m_animatedType);
     ASSERT(resultAnimationElement->m_animatedPropertyType == m_animatedPropertyType);
 
     if (hasTagName(SVGNames::setTag))
         percentage = 1;
 
     if (calcMode() == CalcModeDiscrete)
         percentage = percentage < 0.5 ? 0 : 1;
 
     // Target element might have changed.
@@ skipping 295 matching lines @@
 
 SVGAnimatedTypeAnimator* SVGAnimateElement::ensureAnimator()
 {
     if (!m_animator)
         m_animator = SVGAnimatorFactory::create(this, targetElement(), m_animatedPropertyType);
     ASSERT(m_animatedPropertyType == m_animator->type());
     return m_animator.get();
 }
 
 }