[Gin] Add Arguments::GetHolderCreationContext()

gin/arguments.h

Index: gin/arguments.h
diff --git a/gin/arguments.h b/gin/arguments.h
index 55f9f449e2d226c222f4ced58ce7cdb0369803f8..99a5d16db21c388dc5dc859301e8deb85cc1c1fd 100644
--- a/gin/arguments.h
+++ b/gin/arguments.h
@@ -74,6 +74,9 @@ class GIN_EXPORT Arguments {
     info_->GetReturnValue().Set(v8_value);
   }
 
+  // Returns the creation context of the Holder.
+  v8::Local<v8::Context> GetHolderCreationContext();
+
   // Always check the return value whether the handle is empty before
   // dereferencing the handle.
   v8::Local<v8::Value> PeekNext() const;