Fix broken AttachContext from r152289

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 1754 matching lines @@
 void Document::updateStyleIfNeeded()
 {
     ASSERT(isMainThread());
     ASSERT(!view() || (!view()->isInLayout() && !view()->isPainting()));
 
     if (!m_pendingStyleRecalcShouldForce && !childNeedsStyleRecalc())
         return;
 
     AnimationUpdateBlock animationUpdateBlock(m_frame ? m_frame->animation() : 0);
     recalcStyle(NoChange);
+
+    // As a result of the style recalculation, the currently hovered element might have been
+    // detached (for example, by setting display:none in the :hover style), schedule another mouseMove event
+    // to check if any other elements ended up under the mouse pointer due to re-layout.
+    if (hoverNode() && !hoverNode()->renderer() && frame())
+        frame()->eventHandler()->dispatchFakeMouseMoveEventSoon();

[esprehn, 2013/06/17 22:00:27]

Hmm, there's a number of other places where we might call Document::recalcStyle
(in this file, and perhaps elsewhere). I don't think this is right to check just
here. Did you mean to check inside Document::recalcStyle at the end?

[stavila, 2013/06/18 08:54:00]

Yes, I know Document::recalcStyle is called in multiple places. The most
'correct' place would have been to add that code at the end of the
Document::updateHoverActiveState, after calling Document::updateStyleIfNeeded.
However, this only needs to happen if style updating is 'needed', so I moved
inside Document::updateStyleIfNeeded, after we decided that we do need to
recalcStyle. While it is true that moving it to recalcStyle would not change the
behaviour (everything would still work properly), it would generate unnecessary
work for the CPU, as the current implementation (inside updateStyleIfNeeded)
gets called less often and fully covers the hover situation.

What do you think?

 }
 
 void Document::updateLayout()
 {
     ASSERT(isMainThread());
 
     FrameView* frameView = view();
     if (frameView && frameView->isInLayout()) {
         // View layout should not be re-entrant.
         ASSERT_NOT_REACHED();
@@ skipping 3258 matching lines @@
     RenderObject* newHoverObj = newHoverNode ? newHoverNode->renderer() : 0;
 
     // Locate the common ancestor render object for the two renderers.
     RenderObject* ancestor = nearestCommonHoverAncestor(oldHoverObj, newHoverObj);
 
     Vector<RefPtr<Node>, 32> nodesToRemoveFromChain;
     Vector<RefPtr<Node>, 32> nodesToAddToChain;
 
     if (oldHoverObj != newHoverObj) {
         // If the old hovered node is not nil but it's renderer is, it was probably detached as part of the :hover style
-        // (for instance by setting display:none in the :hover pseudo-class). In this case, the old hovered element
+        // (for instance by setting display:none in the :hover pseudo-class). In this case, the old hovered element (and its ancestors)
         // must be updated, to ensure it's normal style is re-applied.
         if (oldHoverNode && !oldHoverObj) {
-            if (!mustBeInActiveChain || oldHoverNode->inActiveChain())
-                nodesToRemoveFromChain.append(oldHoverNode);
+            for (Node* node = oldHoverNode.get(); node; node = node->parentNode()) {
+                if (!mustBeInActiveChain || (node->isElementNode() && toElement(node)->inActiveChain()))
+                    nodesToRemoveFromChain.append(node);
+            }
+
         }
 
         // The old hover path only needs to be cleared up to (and not including) the common ancestor;
         for (RenderObject* curr = oldHoverObj; curr && curr != ancestor; curr = curr->hoverAncestor()) {
             if (curr->node() && !curr->isText() && (!mustBeInActiveChain || curr->node()->inActiveChain()))
                 nodesToRemoveFromChain.append(curr->node());
         }
     }
 
     // Now set the hover state for our new object up to the root.
@@ skipping 159 matching lines @@
 }
 
 void Document::addLifecycleObserver(DocumentLifecycleObserver* observer)
 {
     if (!m_lifecycleNotifier)
         m_lifecycleNotifier = DocumentLifecycleNotifier::create();
     m_lifecycleNotifier->addObserver(observer);
 }
 
 } // namespace WebCore