Introduce NavigatorID IDL interface

Source/core/page/NavigatorID.h

Index: Source/core/page/NavigatorID.h
diff --git a/Source/core/svg/SVGUnknownElement.cpp b/Source/core/page/NavigatorID.h
similarity index 81%
copy from Source/core/svg/SVGUnknownElement.cpp
copy to Source/core/page/NavigatorID.h
index ecc0d2f2f186434ad83a947d92cca241c2bfa3b0..c235fe0e422afa2fdef603b8178855cc468b02df 100644
--- a/Source/core/svg/SVGUnknownElement.cpp
+++ b/Source/core/page/NavigatorID.h
@@ -28,14 +28,23 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include "config.h"
-#include "core/svg/SVGUnknownElement.h"
+#ifndef NavigatorID_h
+#define NavigatorID_h
+
+#include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
-SVGUnknownElement::SVGUnknownElement(const QualifiedName& tagName, Document* document)
-    : SVGElement(tagName, document)
-{
-}
+class NavigatorBase;
+
+class NavigatorID {
+public:
+    static String appName(const NavigatorBase*);
+    static String appVersion(const NavigatorBase*);
+    static String userAgent(const NavigatorBase*);

[do-not-use, 2013/08/20 11:05:06]

Note that in theory, we could have 2 versions of this userAgent(), one taking a
Navigator* and another taking a WorkerNavigator*. As a result, we the
userAgent() virtual method in WorkerBase would become unnecessary and the
WorkerBase base class would eventually disappear.

I was not sure which way to go:
- Removing WorkerBase and a virtual function call is a plus
- However, the duplication in NavigatorID would not look great

[haraken, 2013/08/20 12:52:52]

I'd prefer sharing code between the main thread and workers as much as possible.
In that sense, the current CL looks better to me.

+    static String platform(const NavigatorBase*);
+};
 
 } // namespace WebCore
+
+#endif // NavigatorID_h