[SVG] SVGAnimatedRect migration to new SVG property impl.

Source/core/svg/properties/NewSVGAnimatedProperty.h

Index: Source/core/svg/properties/NewSVGAnimatedProperty.h
diff --git a/Source/core/svg/properties/NewSVGAnimatedProperty.h b/Source/core/svg/properties/NewSVGAnimatedProperty.h
index f0ef356552d02d2068e04acfe9e7ab3c9fa48d2f..75774001cd68ef768d53569e874b485b4b9a849d 100644
--- a/Source/core/svg/properties/NewSVGAnimatedProperty.h
+++ b/Source/core/svg/properties/NewSVGAnimatedProperty.h
@@ -137,7 +137,6 @@ public:
         TrackExceptionState es;
 
         m_baseValue->setValueAsString(value, es);
-        commitChange();
 
         if (es.hadException())
             parseError = ParsingAttributeFailedError;
@@ -213,8 +212,11 @@ public:
     // Use currentValue() from C++ code.
     virtual TearOffType* baseVal()
     {
-        if (!m_baseValTearOff)
+        if (!m_baseValTearOff) {
             m_baseValTearOff = TearOffType::create(this->baseValue(), this->contextElement(), PropertyIsNotAnimVal, this->attributeName());
+            if (this->isReadOnly())
+                m_baseValTearOff->setIsReadOnlyProperty();
+        }
 
         return m_baseValTearOff.get();
     }