SVG: Remove SVGAnimatedPropertyBase::startAnimation and its overrides which are already all NOOP

Source/core/svg/SVGAnimatedNumberOptionalNumber.h

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 30 matching lines @@
 // while DOM attribute and SMIL animations operate on this class.
 // From Javascript, the two SVGAnimatedNumbers |firstNumber| and |secondNumber| are used.
 // For example, see SVGFEDropShadowElement::stdDeviation{X,Y}()
 class SVGAnimatedNumberOptionalNumber : public SVGAnimatedPropertyCommon<SVGNumberOptionalNumber> {
 public:
     static PassRefPtr<SVGAnimatedNumberOptionalNumber> create(SVGElement* contextElement, const QualifiedName& attributeName, float initialFirstValue = 0, float initialSecondValue = 0)
     {
         return adoptRef(new SVGAnimatedNumberOptionalNumber(contextElement, attributeName, initialFirstValue, initialSecondValue));
     }
 
-    virtual void animationStarted() OVERRIDE;
     virtual void setAnimatedValue(PassRefPtr<SVGPropertyBase>) OVERRIDE;
     virtual bool needsSynchronizeAttribute() OVERRIDE;
     virtual void animationEnded() OVERRIDE;
 
     SVGAnimatedNumber* firstNumber() { return m_firstNumber.get(); }
     SVGAnimatedNumber* secondNumber() { return m_secondNumber.get(); }
 
 protected:
     SVGAnimatedNumberOptionalNumber(SVGElement* contextElement, const QualifiedName& attributeName, float initialFirstValue, float initialSecondValue);
 
     RefPtr<SVGAnimatedNumber> m_firstNumber;
     RefPtr<SVGAnimatedNumber> m_secondNumber;
 };
 
 } // namespace WebCore
 
 #endif // SVGAnimatedNumberOptionalNumber_h