Optimize (slightly) Document::updateHoverActiveState.

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 5070 matching lines @@
     // Now set the hover state for our new object up to the root.
     for (RenderObject* curr = newHoverObj; curr; curr = curr->hoverAncestor()) {
         if (curr->node() && !curr->isText() && (!mustBeInActiveChain || curr->node()->inActiveChain()))
             nodesToAddToChain.append(curr->node());
     }
 
     size_t removeCount = nodesToRemoveFromChain.size();
     for (size_t i = 0; i < removeCount; ++i)
         nodesToRemoveFromChain[i]->setHovered(false);
 
+    bool sawCommonAncestor = false;
     size_t addCount = nodesToAddToChain.size();
     for (size_t i = 0; i < addCount; ++i) {
+        // Elements past the common ancestor do not change hover state, but might change active state.
+        if (ancestor && nodesToAddToChain[i] == ancestor->node())
+            sawCommonAncestor = true;
         if (allowActiveChanges)
             nodesToAddToChain[i]->setActive(true);
-        nodesToAddToChain[i]->setHovered(true);
+        if (!sawCommonAncestor)
+            nodesToAddToChain[i]->setHovered(true);
     }
 
     updateStyleIfNeeded();
 }
 
 void Document::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::DOM);
     ContainerNode::reportMemoryUsage(memoryObjectInfo);
     TreeScope::reportMemoryUsage(memoryObjectInfo);
@@ skipping 138 matching lines @@
 {
     return DocumentLifecycleNotifier::create(this);
 }
 
 DocumentLifecycleNotifier* Document::lifecycleNotifier()
 {
     return static_cast<DocumentLifecycleNotifier*>(ScriptExecutionContext::lifecycleNotifier());
 }
 
 } // namespace WebCore