Avoid unnecessary style recalc for subtree of focused element.

Source/core/dom/ContainerNode.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 787 matching lines @@
 }
 
 // This is used by FrameSelection to denote when the active-state of the page has changed
 // independent of the focused element changing.
 void ContainerNode::focusStateChanged()
 {
     // If we're just changing the window's active state and the focused node has no
     // renderer we can just ignore the state change.
     if (!renderer())
         return;
-    // FIXME: This could probably setNeedsStyleRecalc(LocalStyleChange) in the affectedByFocus case
-    // and only setNeedsStyleRecalc(SubtreeStyleChange) in the childrenAffectedByFocus case.
-    if (renderStyle()->affectedByFocus() || (isElementNode() && toElement(this)->childrenAffectedByFocus()))
+
+    if (isElementNode() && toElement(this)->childrenAffectedByFocus())
         setNeedsStyleRecalc();
+    else if (renderStyle()->affectedByFocus())
+        setNeedsStyleRecalc(LocalStyleChange);
+
     if (renderer() && renderer()->style()->hasAppearance())
         RenderTheme::theme().stateChanged(renderer(), FocusState);
 }
 
 void ContainerNode::setFocus(bool received)
 {
     if (focused() == received)
         return;
 
     Node::setFocus(received);
 
     focusStateChanged();
+
+    if (renderer() || received)
+        return;
+
     // If :focus sets display: none, we lose focus but still need to recalc our style.
-    if (!renderer() && !received)
+    if (isElementNode() && toElement(this)->childrenAffectedByFocus())
         setNeedsStyleRecalc();
+    else
+        setNeedsStyleRecalc(LocalStyleChange);
 }
 
 void ContainerNode::setActive(bool down)
 {
     if (down == active())
         return;
 
     Node::setActive(down);
 
     // FIXME: Why does this not need to handle the display: none transition like :hover does?
@@ skipping 214 matching lines @@
         return true;
 
     if (node->isElementNode() && toElement(node)->shadow())
         return true;
 
     return false;
 }
 #endif
 
 } // namespace WebCore