Only restore dialog focus if focus is in dialog

https://bugs.webkit.org/show_bug.cgi?id=256717
rdar://109572320

Reviewed by NOBODY (OOPS!).

Implement whatwg/html#9178 to avoid unexpected focus shifting when focus is already outside of the dialog.

* LayoutTests/imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/dialog-focus-previous-outside-expected.txt:
* Source/WebCore/html/HTMLDialogElement.cpp:
(WebCore::HTMLDialogElement::close):

LayoutTests/imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/dialog-focus-previous-outside-expected.txt

@@ -1,10 +1,8 @@
 button 1 button 2
 
-FAIL Focus should not be restored if the currently focused element is not inside the dialog. assert_equals: expected Element node <button id="b2">button 2</button> but got Element node <button id="b1">button 1</button>
-FAIL Focus restore should not occur when the focused element is in a shadowroot outside of the dialog. assert_equals: document.activeElement should point at the shadow host. expected Element node <div id="host">
-
-</div> but got Element node <button id="b2">button 2</button>
+PASS Focus should not be restored if the currently focused element is not inside the dialog.
+PASS Focus restore should not occur when the focused element is in a shadowroot outside of the dialog.
 PASS Focus restore should occur when the focused element is in a shadowroot inside the dialog.
-PASS Focus restore should occur when the focused element is slotted into a dialog.
+FAIL Focus restore should occur when the focused element is slotted into a dialog. assert_equals: expected Element node <button id="b2">button 2</button> but got Element node <button id="host2button">button</button>
 PASS Focus restore should always occur for modal dialogs.
 

Source/WebCore/html/HTMLDialogElement.cpp

@@ -126,7 +126,9 @@ void HTMLDialogElement::close(const String& result)
 
     setBooleanAttribute(openAttr, false);
 
-    if (isModal())
+    bool wasModal = isModal();
+
+    if (wasModal)
         removeFromTopLayer();
 
     setIsModal(false);
@@ -135,9 +137,12 @@ void HTMLDialogElement::close(const String& result)
         m_returnValue = result;
 
     if (RefPtr element = std::exchange(m_previouslyFocusedElement, nullptr).get()) {
-        FocusOptions options;
-        options.preventScroll = true;
-        element->focus(options);
+        RefPtr focusedElement = document().focusedElement();
+        if ((focusedElement && containsIncludingShadowDOM(focusedElement)) || wasModal) {
+            FocusOptions options;
+            options.preventScroll = true;
+            element->focus(options);
+        }
     }
 
     queueTaskToDispatchEvent(TaskSource::UserInteraction, Event::create(eventNames().closeEvent, Event::CanBubble::No, Event::IsCancelable::No));