Gin: Make it easier to implement Wrappable

mojo/apps/js/bindings/waiting_callback.h

Index: mojo/apps/js/bindings/waiting_callback.h
diff --git a/mojo/apps/js/bindings/waiting_callback.h b/mojo/apps/js/bindings/waiting_callback.h
index e8721e3683aa2ce0a377ef36c00b12b9f3cd2b53..8bc762851ecb498fcdf70d8e973b047b6296900d 100644
--- a/mojo/apps/js/bindings/waiting_callback.h
+++ b/mojo/apps/js/bindings/waiting_callback.h
@@ -13,14 +13,12 @@
 namespace mojo {
 namespace js {
 
-class WaitingCallback : public gin::Wrappable,
+class WaitingCallback : public gin::Wrappable<WaitingCallback>,
                         public BindingsSupport::AsyncWaitCallback {
  public:
   static gin::Handle<WaitingCallback> Create(
       v8::Isolate* isolate, v8::Handle<v8::Function> callback);
 
-  static gin::WrapperInfo kWrapperInfo;
-  virtual gin::WrapperInfo* GetWrapperInfo() OVERRIDE;
   static void EnsureRegistered(v8::Isolate* isolate);
 
   BindingsSupport::AsyncWaitID wait_id() const {