Fix broken AttachContext from r152289

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 6f0e65b65d5f8070dafac6d173eb755a75ec4c26..309b3a9d8f1cfb7c9e201fe77cf56e0ee0e69e57 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -1772,6 +1772,12 @@ void Document::updateStyleIfNeeded()
 
     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()
@@ -5050,11 +5056,14 @@ void Document::updateHoverActiveState(const HitTestRequest& request, Element* in
 
     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;