LibWeb: Remove page_did_set_document_in_top_level_browsing_context()

This PageClient callback was never used for anything.

Userland/Libraries/LibWeb/HTML/BrowsingContext.cpp

@@ -98,9 +98,6 @@ void BrowsingContext::set_active_document(DOM::Document* document)
         if (m_page && is_top_level())
             m_page->client().page_did_change_title(m_active_document->title());
     }
-
-    if (m_page)
-        m_page->client().page_did_set_document_in_top_level_browsing_context(m_active_document);
 }
 
 void BrowsingContext::set_viewport_rect(Gfx::IntRect const& rect)

Userland/Libraries/LibWeb/Page/Page.h

@@ -84,7 +84,6 @@ public:
     virtual Gfx::Palette palette() const = 0;
     virtual Gfx::IntRect screen_rect() const = 0;
     virtual CSS::PreferredColorScheme preferred_color_scheme() const = 0;
-    virtual void page_did_set_document_in_top_level_browsing_context(DOM::Document*) { }
     virtual void page_did_change_title(String const&) { }
     virtual void page_did_start_loading(const AK::URL&) { }
     virtual void page_did_finish_loading(const AK::URL&) { }

Userland/Utilities/headless-browser.cpp

@@ -125,10 +125,6 @@ public:
     {
     }
 
-    virtual void page_did_set_document_in_top_level_browsing_context(Web::DOM::Document*) override
-    {
-    }
-
     virtual void page_did_start_loading(AK::URL const&) override
     {
     }