dialog: Set 'autofocus process flag' to true at the end of dialog focusing steps

- Unify multiple |focus(); return;| in SetFocusForDialog() into one.
- Add origin check and FinalizeAutofocus() call to SetFocusForDialog().

Bug: 985637
Change-Id: Ibb9a7161f384c9d15452dd2559c69cb0d458b9da

Experimental implementation for https://github.com/whatwg/html/pull/4918

Bug: 985637
Change-Id: I321736d512d6d8c76095f0f6de8751cd0a5e44e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1911061Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714672}

third_party/blink/renderer/core/dom/document.cc

@@ -7904,9 +7904,8 @@ void Document::FlushAutofocusCandidates() {
         // https://github.com/whatwg/html/issues/5027
         element.DelegatesFocus()) {
       // 9.1. Empty candidates.
-      autofocus_candidates_.clear();
       // 9.2. Set topDocument's autofocus processed flag to true.
-      autofocus_processed_flag_ = true;
+      FinalizeAutofocus();
       // 9.3. Run the focusing steps for element.
       element.focus();
     } else {
@@ -7916,6 +7915,11 @@ void Document::FlushAutofocusCandidates() {
   }
 }
 
+void Document::FinalizeAutofocus() {
+  autofocus_candidates_.clear();
+  autofocus_processed_flag_ = true;
+}
+
 bool Document::HasNonEmptyFragment() const {
   return !Url().FragmentIdentifier().IsEmpty();
 }

third_party/blink/renderer/core/dom/document.h

@@ -840,6 +840,7 @@ class CORE_EXPORT Document : public ContainerNode,
   void EnqueueAutofocusCandidate(Element&);
   bool HasAutofocusCandidates() const;
   void FlushAutofocusCandidates();
+  void FinalizeAutofocus();
   void SetSequentialFocusNavigationStartingPoint(Node*);
   Element* SequentialFocusNavigationStartingPoint(WebFocusType) const;
 

third_party/blink/renderer/core/html/html_dialog_element.cc

@@ -39,10 +39,11 @@
 
 namespace blink {
 
+// https://html.spec.whatwg.org/C/#the-dialog-element
 // This function chooses the focused element when show() or showModal() is
 // invoked, as described in their spec.
 static void SetFocusForDialog(HTMLDialogElement* dialog) {
-  Element* focusable_descendant = nullptr;
+  Element* control = nullptr;
   Node* next = nullptr;
 
   // TODO(kochi): How to find focusable element inside Shadow DOM is not
@@ -57,24 +58,35 @@ static void SetFocusForDialog(HTMLDialogElement* dialog) {
     if (!element)
       continue;
     if (element->IsAutofocusable() && element->IsFocusable()) {
-      element->focus();
-      return;
+      control = element;
+      break;
     }
-    if (!focusable_descendant && element->IsFocusable())
-      focusable_descendant = element;
+    if (!control && element->IsFocusable())
+      control = element;
   }
+  if (!control)
+    control = dialog;
 
-  if (focusable_descendant) {
-    focusable_descendant->focus();
-    return;
-  }
+  // 3. Run the focusing steps for control.
+  if (control->IsFocusable())
+    control->focus();
+  else
+    dialog->GetDocument().ClearFocusedElement();
 
-  if (dialog->IsFocusable()) {
-    dialog->focus();
+  // 4. Let topDocument be the active document of control's node document's
+  // browsing context's top-level browsing context.
+  // 5. If control's node document's origin is not the same as the origin of
+  // topDocument, then return.
+  Document& doc = control->GetDocument();
+  if (!doc.IsActive())
+    return;
+  if (!doc.IsInMainFrame() &&
+      !doc.TopFrameOrigin()->CanAccess(doc.GetSecurityOrigin()))
     return;
-  }
 
-  dialog->GetDocument().ClearFocusedElement();
+  // 6. Empty topDocument's autofocus candidates.
+  // 7. Set topDocument's autofocus processed flag to true.
+  doc.TopDocument().FinalizeAutofocus();
 }
 
 static void InertSubtreesChanged(Document& document) {

third_party/blink/web_tests/external/wpt/html/semantics/interactive-elements/the-dialog-element/dialog-autofocus-just-once-expected.txt

-This is a testharness.js-based test.
-FAIL An autofocus element in a dialog element should not try to get focus twice. assert_equals: Non-dialog autofocus processing should be skipped. expected Element node <body>
-<dialog open="">
-<input>
-<input autofocus="">
-</di... but got Element node <input autofocus=""></input>
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/html/semantics/interactive-elements/the-dialog-element/dialog-focusing-steps-prevent-autofocus-expected.txt

-This is a testharness.js-based test.
-FAIL After showing a dialog, non-dialog autofocus processing won't work. assert_equals: Non-dialog autofocus processing should be skipped. expected Element node <body>
-<input autofocus=""><dialog></dialog>
-<script>
-// ... but got Element node <input autofocus=""></input>
-Harness: the test ran to completion.
-