Introduce a SVGUnknownElement class for unknown SVG elements

Source/core/svg/SVGUnknownElement.h

Index: Source/core/svg/SVGUnknownElement.h
diff --git a/Source/core/svg/SVGNumber.h b/Source/core/svg/SVGUnknownElement.h
similarity index 65%
copy from Source/core/svg/SVGNumber.h
copy to Source/core/svg/SVGUnknownElement.h
index db47ed0dfb2ec33e7d6a538895fe9d8ff16ba61c..fe8d7e4dbe5dee0d8ab8123998113a7436b78e85 100644
--- a/Source/core/svg/SVGNumber.h
+++ b/Source/core/svg/SVGUnknownElement.h
@@ -28,49 +28,32 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef SVGNumber_h
-#define SVGNumber_h
+#ifndef SVGUnknownElement_h
+#define SVGUnknownElement_h
 
-#include "core/svg/properties/SVGPropertyTraits.h"
+#include "core/svg/SVGElement.h"
 
 namespace WebCore {
 
-class SVGNumber {
-    WTF_MAKE_FAST_ALLOCATED;
+// This type is used for 2 kinds of elements:
+// - Unknown Elements in SVG namespace
+// - Registered custom tag elements in SVG namespace (http://www.w3.org/TR/2013/WD-custom-elements-20130514/#registering-custom-elements)
+//
+// The main purpose of this class at the moment is to override rendererIsNeeded() to return
+// false to make sure we don't attempt to render such elements.
+class SVGUnknownElement : public SVGElement {
 public:
-    SVGNumber()
-        : m_value(0)
+    static PassRefPtr<SVGUnknownElement> create(const QualifiedName& tagName, Document* document)
     {
+        return adoptRef(new SVGUnknownElement(tagName, document));
     }
 
-    SVGNumber(float value)
-        : m_value(value)
-    {
-    }
-
-    SVGNumber& operator+=(const SVGNumber& rhs)
-    {
-        m_value += rhs.value();
-        return *this;
-    }
-
-    float value() const { return m_value; }
-    float& valueRef() { return m_value; }
-    String valueAsString() const { return String::number(m_value); }
-    void setValue(float value) { m_value = value; }
-
 private:
-    float m_value;
-};
-
-COMPILE_ASSERT(sizeof(SVGNumber) == sizeof(float), SVGNumber_same_size_as_float);
+    SVGUnknownElement(const QualifiedName&, Document*);
 
-template<>
-struct SVGPropertyTraits<SVGNumber> {
-    static SVGNumber initialValue() { return SVGNumber(); }
-    static String toString(const SVGNumber& type) { return type.valueAsString(); }
+    virtual bool rendererIsNeeded(const NodeRenderingContext&) OVERRIDE { return false; }
 };
 
 } // namespace WebCore
 
-#endif // SVGNumber_h
+#endif // SVGUnknownElement_h