[webkit-dev] Clients and the Page constructor

[Steve Block]

> That still makes it required to add null checks for some (or all) of
> the clients.  Something we've avoided in the past.
This wouldn't add a need for null checks. The structure would only be
for clients for optional features. If the feature is enabled, the
client must be non-null. This is no different from the case with the
individual arguments used currently.