- // Returns true if for the navigation from |current_entry| to |new_entry|,
- // a new SiteInstance and BrowsingInstance should be created (even if we are
- // in a process model that doesn't usually swap). This forces a process swap
- // and severs script connections with existing tabs. Cases where this can
- // happen include transitions between WebUI and regular web pages.
- // Either of the entries may be NULL.
+ // Returns true if for the navigation from |current_effective_url| to
+ // |new_effective_url|, a new SiteInstance and BrowsingInstance should be
+ // created (even if we are in a process model that doesn't usually swap).
+ // This forces a process swap and severs script connections with existing
+ // tabs. Cases where this can happen include transitions between WebUI and
+ // regular web pages. |new_site_instance| may be null.
+ // If there is no current NavigationEntry, then |current_is_view_source_mode|
+ // should be the same as |new_is_view_source_mode|.
+ //
+ // We use the effective URL here, since that's what is used in the
+ // SiteInstance's site and when we later call IsSameWebSite. If there is no
+ // current NavigationEntry, check the current SiteInstance's site, which might
+ // already be committed to a Web UI URL (such as the NTP).