Gin: Make it easier to implement Wrappable

gin/function_template.h.pump

Index: gin/function_template.h.pump
diff --git a/gin/function_template.h.pump b/gin/function_template.h.pump
index 23941c08287209c8eb03c2d8d92d5e6c0a57d8b0..ed92c31f90816796eff0b4dd4ab6c5ed68833924 100644
--- a/gin/function_template.h.pump
+++ b/gin/function_template.h.pump
@@ -58,10 +58,9 @@ struct CallbackParamTraits<const T*> {
 // It inherits from Wrappable, which delete itself when both (a) the refcount
 // via base::RefCounted has dropped to zero, and (b) there are no more
 // JavaScript references in V8.
+//
+// TODO(aa): Do we still need the separate base class?
 class CallbackHolderBase : public Wrappable {
- public:
-  virtual WrapperInfo* GetWrapperInfo() OVERRIDE;
-  static WrapperInfo kWrapperInfo;
  protected:
   virtual ~CallbackHolderBase() {}
 };