Allow an element in shadow tree in <dialog> to be initially focused.

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 10 matching lines @@
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/html/HTMLDialogElement.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/ExceptionCode.h"
-#include "core/dom/NodeTraversal.h"
+#include "core/dom/shadow/FlatTreeTraversal.h"
 #include "core/events/Event.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/UseCounter.h"
 #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);
+  Element* focusableDescendant = nullptr;
+  Node* next = nullptr;
+
+  // TODO(kochi): How to find focusable element inside Shadow DOM is not
+  // currently specified.  This may change at any time.
+  // See crbug/383230 and https://github.com/whatwg/html/issue/2393 .
+  for (Node* node = FlatTreeTraversal::firstChild(*dialog); node; node = next) {
+    next = isHTMLDialogElement(*node)
+               ? FlatTreeTraversal::nextSkippingChildren(*node, dialog)
+               : FlatTreeTraversal::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;
       }
@@ skipping 144 matching lines @@
 void HTMLDialogElement::defaultEventHandler(Event* event) {
   if (event->type() == EventTypeNames::cancel) {
     closeDialog();
     event->setDefaultHandled();
     return;
   }
   HTMLElement::defaultEventHandler(event);
 }
 
 }  // namespace blink