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

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

Index: third_party/WebKit/Source/core/html/HTMLDialogElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLDialogElement.cpp b/third_party/WebKit/Source/core/html/HTMLDialogElement.cpp
index 9edc5883e4ea38e02f6a61618fe0434fdac93113..118d713e9420f0c19b72dc86e517a1caebda40af 100644
--- a/third_party/WebKit/Source/core/html/HTMLDialogElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLDialogElement.cpp
@@ -42,39 +42,27 @@ 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 (!focusableDescendant && element->isFocusable())
-      focusableDescendant = element;
-  }
 
-  if (focusableDescendant) {
-    focusableDescendant->focus();
-    return;
-  }
+    Element* element = toElement(node);
+    if (!element->isFormControlElement())
+      continue;
 
-  if (dialog->isFocusable()) {
-    dialog->focus();
-    return;
+    HTMLFormControlElement* control = toHTMLFormControlElement(node);
+    if (control->isAutofocusable() && control->isFocusable()) {
+      control->focus();
+      return;
+    }
   }
 
-  dialog->document().clearFocusedElement();
+  dialog->focus();
 }
 
 static void inertSubtreesChanged(Document& document) {
@@ -212,4 +200,12 @@ void HTMLDialogElement::defaultEventHandler(Event* event) {
   HTMLElement::defaultEventHandler(event);
 }
 
+bool HTMLDialogElement::supportsFocus() const {
+  return true;
+}
+
+int HTMLDialogElement::tabIndex() const {
+  return hasTabIndex() ? getIntegralAttribute(tabindexAttr) : -1;
+}
+
 }  // namespace blink