Implement ShadowRoot.delegatesFocus 3/4 (Slide focus on focus() method)

Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 2175 matching lines @@
     if (document().focusedElement() == this)
         return;
 
     if (!document().isActive())
         return;
 
     document().updateLayoutIgnorePendingStylesheets();
     if (!isFocusable())
         return;
 
+    if (shadowRoot() && shadowRoot()->delegatesFocus()) {
+        if (containsIncludingShadowDOM(document().focusedElement()))
+            return;
+
+        // Slide the focus to its inner node.
+        Node* next = document().page()->focusController().findFocusableNode(WebFocusTypeForward, *this);
+        if (next && next->isElementNode() && containsIncludingShadowDOM(next)) {
+            toElement(next)->focus(false, WebFocusTypeForward);
+            return;
+        }
+    }
+
     RefPtrWillBeRawPtr<Node> protect(this);
     if (!document().page()->focusController().setFocusedElement(this, document().frame(), type))
         return;
 
     // Setting the focused node above might have invalidated the layout due to scripts.
     document().updateLayoutIgnorePendingStylesheets();
     if (!isFocusable())
         return;
 
     cancelFocusAppearanceUpdate();
@@ skipping 1188 matching lines @@
 {
 #if ENABLE(OILPAN)
     if (hasRareData())
         visitor->trace(elementRareData());
     visitor->trace(m_elementData);
 #endif
     ContainerNode::trace(visitor);
 }
 
 } // namespace blink