LibWeb: Make Window.getSelection() forward to Document.getSelection()

(And have document create the Selection object on demand.)

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -67,6 +67,7 @@
 #include <LibWeb/Page/Page.h>
 #include <LibWeb/Platform/Timer.h>
 #include <LibWeb/SVG/TagNames.h>
+#include <LibWeb/Selection/Selection.h>
 #include <LibWeb/UIEvents/EventNames.h>
 #include <LibWeb/UIEvents/FocusEvent.h>
 #include <LibWeb/UIEvents/KeyboardEvent.h>
@@ -335,6 +336,7 @@ void Document::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_forms);
     visitor.visit(m_scripts);
     visitor.visit(m_all);
+    visitor.visit(m_selection);
 
     for (auto& script : m_scripts_to_execute_when_parsing_has_finished)
         visitor.visit(script.ptr());
@@ -350,6 +352,20 @@ void Document::visit_edges(Cell::Visitor& visitor)
         visitor.visit(target.ptr());
 }
 
+// https://w3c.github.io/selection-api/#dom-document-getselection
+JS::GCPtr<Selection::Selection> Document::get_selection()
+{
+    // The method must return the selection associated with this if this has an associated browsing context,
+    // and it must return null otherwise.
+    if (!browsing_context()) {
+        return nullptr;
+    }
+    if (!m_selection) {
+        m_selection = Selection::Selection::create(realm());
+    }
+    return m_selection;
+}
+
 // https://html.spec.whatwg.org/multipage/dynamic-markup-insertion.html#dom-document-write
 WebIDL::ExceptionOr<void> Document::write(Vector<String> const& strings)
 {

Userland/Libraries/LibWeb/DOM/Document.h

@@ -87,6 +87,9 @@ public:
     static JS::NonnullGCPtr<Document> construct_impl(JS::Realm&);
     virtual ~Document() override;
 
+    // https://w3c.github.io/selection-api/#dom-document-getselection
+    JS::GCPtr<Selection::Selection> get_selection();
+
     size_t next_layout_node_serial_id(Badge<Layout::Node>) { return m_next_layout_node_serial_id++; }
     size_t layout_node_count() const { return m_next_layout_node_serial_id; }
 
@@ -592,6 +595,8 @@ private:
 
     // https://html.spec.whatwg.org/multipage/dom.html#previous-document-unload-timing
     DocumentUnloadTimingInfo m_previous_document_unload_timing;
+
+    JS::GCPtr<Selection::Selection> m_selection;
 };
 
 }

Userland/Libraries/LibWeb/HTML/Window.cpp

@@ -525,13 +525,6 @@ int Window::screen_y() const
     return 0;
 }
 
-// https://w3c.github.io/selection-api/#dom-window-getselection
-Selection::Selection* Window::get_selection_impl()
-{
-    // FIXME: Implement.
-    return nullptr;
-}
-
 // https://html.spec.whatwg.org/multipage/webstorage.html#dom-localstorage
 JS::NonnullGCPtr<HTML::Storage> Window::local_storage()
 {
@@ -1241,10 +1234,12 @@ JS_DEFINE_NATIVE_FUNCTION(Window::get_computed_style)
     return impl->get_computed_style_impl(*static_cast<DOM::Element*>(object));
 }
 
+// https://w3c.github.io/selection-api/#dom-window-getselection
 JS_DEFINE_NATIVE_FUNCTION(Window::get_selection)
 {
+    // The method must invoke and return the result of getSelection() on this's Window.document attribute.
     auto* impl = TRY(impl_from(vm));
-    return impl->get_selection_impl();
+    return impl->associated_document().get_selection();
 }
 
 JS_DEFINE_NATIVE_FUNCTION(Window::match_media)

Userland/Libraries/LibWeb/HTML/Window.h

@@ -102,8 +102,6 @@ public:
     int screen_x() const;
     int screen_y() const;
 
-    Selection::Selection* get_selection_impl();
-
     JS::NonnullGCPtr<HTML::Storage> local_storage();
     JS::NonnullGCPtr<HTML::Storage> session_storage();