Add number() static methods to AtomicString class

Source/wtf/text/IntegerToStringConversion.h

Index: Source/wtf/text/IntegerToStringConversion.h
diff --git a/Source/wtf/text/IntegerToStringConversion.h b/Source/wtf/text/IntegerToStringConversion.h
index 0962352eb026586054ea371035a8fc4211357959..df63448e2b618445a561c102ca91ce621bd14ed5 100644
--- a/Source/wtf/text/IntegerToStringConversion.h
+++ b/Source/wtf/text/IntegerToStringConversion.h
@@ -44,6 +44,11 @@ template<> struct ConversionTrait<StringBuilder> {
     typedef StringBuilder AdditionalArgumentType;
     static inline ReturnType flush(LChar* characters, unsigned length, StringBuilder* stringBuilder) { stringBuilder->append(characters, length); }
 };
+template<> struct ConversionTrait<AtomicString> {
+    typedef AtomicString ReturnType;
+    typedef void AdditionalArgumentType;
+    static inline ReturnType flush(LChar* characters, unsigned length, void*) { return AtomicString(characters, length); }
+};
 
 template<typename T> struct UnsignedIntegerTrait;