Oilpan: Prepare moving AXObject to heap

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 9b0511ddc6e663203c3e32580568af971fab7083..e7d7f5eb112a1e435c21a02c82d9ae9e685e7b26 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -2127,8 +2127,13 @@ void Document::detach(const AttachContext& context)
             frameHost()->chromeClient().focusedNodeChanged(oldFocusedElement.get(), nullptr);
     }
 
-    if (this == &axObjectCacheOwner())
+    if (this == &axObjectCacheOwner()) {
         clearAXObjectCache();
+    } else if (AXObjectCache* cache = existingAXObjectCache()) {
+        for (Element& element : ElementTraversal::descendantsOf(*this)) {
+            cache->remove(&element);

[dmazzoni, 2015/06/08 15:25:49]

What would happen if we called AXObjectCache::getOrCreate and passed it one of
these elements immediately after this call? Would it correctly return null
because these elements are not attached to a document?

What I'm worried about is that when we remove an element from the cache, that
triggers calling childrenChanged on the parent node - and in some cases that may
try to use element traversal to find the parent and construct a new AXObject
from it.

+        }
+    }
 
     m_layoutView = nullptr;
     ContainerNode::detach(context);