Add number() static methods to AtomicString class

Source/core/dom/Element.h

Index: Source/core/dom/Element.h
diff --git a/Source/core/dom/Element.h b/Source/core/dom/Element.h
index 20699128cd1e15f865d21f6cfe46d9ab085d989d..f151970778a96e3eb8e6af99b6f62da0c50dfccd 100644
--- a/Source/core/dom/Element.h
+++ b/Source/core/dom/Element.h
@@ -114,6 +114,8 @@ public:
     void setIntegralAttribute(const QualifiedName& attributeName, int value);
     unsigned getUnsignedIntegralAttribute(const QualifiedName& attributeName) const;
     void setUnsignedIntegralAttribute(const QualifiedName& attributeName, unsigned value);
+    double getFloatingPointAttribute(const QualifiedName& attributeName, double fallbackValue = std::numeric_limits<double>::quiet_NaN()) const;
+    void setFloatingPointAttribute(const QualifiedName& attributeName, double value);
 
     // Call this to get the value of an attribute that is known not to be the style
     // attribute or one of the SVG animatable attributes.