Re-work <dialog>#show*() focus algorithm

third_party/WebKit/Source/core/html/HTMLDialogElement.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 24 matching lines @@
 #include "core/html/HTMLFormControlElement.h"
 #include "core/style/ComputedStyle.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 // This function chooses the focused element when show() or showModal() is
 // invoked, as described in their spec.
 static void setFocusForDialog(HTMLDialogElement* dialog) {
-  Element* focusableDescendant = 0;
   Node* next = 0;
   for (Node* node = dialog->firstChild(); node; node = next) {
-    if (isHTMLDialogElement(*node))
-      next = NodeTraversal::nextSkippingChildren(*node, dialog);
-    else
-      next = NodeTraversal::next(*node, dialog);
+    next = isHTMLDialogElement(*node)
+               ? NodeTraversal::nextSkippingChildren(*node, dialog)

[esprehn, 2016/12/01 00:39:58]

I think this should probably cross shadow boundaries?

[Dan Beam, 2016/12/01 01:37:27]

I agree but we talked over chat and you were OK with separating these fixes
(i.e. letting me do a followup CL to address looking through shadow DOM)

+               : NodeTraversal::next(*node, dialog);
 
     if (!node->isElementNode())
       continue;
+
     Element* element = toElement(node);
-    if (element->isFormControlElement()) {
-      HTMLFormControlElement* control = toHTMLFormControlElement(node);
-      if (control->isAutofocusable() && control->isFocusable()) {
-        control->focus();
-        return;
-      }
+    if (!element->isFormControlElement())
+      continue;
+
+    HTMLFormControlElement* control = toHTMLFormControlElement(node);
+    if (control->isAutofocusable() && control->isFocusable()) {
+      control->focus();
+      return;
     }
-    if (!focusableDescendant && element->isFocusable())
-      focusableDescendant = element;
   }
 
-  if (focusableDescendant) {
-    focusableDescendant->focus();
-    return;
-  }
-
-  if (dialog->isFocusable()) {
-    dialog->focus();
-    return;
-  }
-
-  dialog->document().clearFocusedElement();
+  dialog->focus();
 }
 
 static void inertSubtreesChanged(Document& document) {
   // When a modal dialog opens or closes, nodes all over the accessibility
   // tree can change inertness which means they must be added or removed from
   // the tree. The most foolproof way is to clear the entire tree and rebuild
   // it, though a more clever way is probably possible.
   document.clearAXObjectCache();
   if (AXObjectCache* cache = document.axObjectCache())
     cache->childrenChanged(&document);
@@ skipping 117 matching lines @@
 
 void HTMLDialogElement::defaultEventHandler(Event* event) {
   if (event->type() == EventTypeNames::cancel) {
     closeDialog();
     event->setDefaultHandled();
     return;
   }
   HTMLElement::defaultEventHandler(event);
 }
 
+bool HTMLDialogElement::supportsFocus() const {
+  return true;
+}
+
+int HTMLDialogElement::tabIndex() const {
+  return hasTabIndex() ? getIntegralAttribute(tabindexAttr) : -1;
+}
+
 }  // namespace blink