Oilpan: Make the Node hierarchy RefCountedGarbageCollected instead of TreeShared.

Source/core/dom/Node.cpp

Index: Source/core/dom/Node.cpp
diff --git a/Source/core/dom/Node.cpp b/Source/core/dom/Node.cpp
index 0798dda6c5b079fdd35680c844fb3a3dd533d867..842b160729c370a2f0f5deef97474bab4ab56312 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -274,14 +274,12 @@ Node::~Node()
 #if !ENABLE(OILPAN)
     if (!isContainerNode())
         willBeDeletedFromDocument();
-#endif
 
     if (m_previous)
         m_previous->setNextSibling(0);
     if (m_next)
         m_next->setPreviousSibling(0);
 
-#if !ENABLE(OILPAN)
     if (m_treeScope)
         m_treeScope->guardDeref();
 #endif
@@ -2375,13 +2373,8 @@ bool Node::willRespondToTouchEvents()
     return hasEventListeners(EventTypeNames::touchstart) || hasEventListeners(EventTypeNames::touchmove) || hasEventListeners(EventTypeNames::touchcancel) || hasEventListeners(EventTypeNames::touchend);
 }
 
+#if !ENABLE(OILPAN)
 // This is here for inlining
-#if ENABLE(OILPAN)
-inline void TreeScope::removedLastRefToScope()
-{
-    dispose();

[haraken, 2014/05/06 15:59:42]

I agree that we're going toward a right direction, but might need to keep in
mind that this change can cause some web-exposed behavior change. Before this
CL, Document was disposed when the last ref to the TreeScope is gone. After this
CL, Document is disposed when the Document is detached. This means that the
point where the Document is disposed becomes earlier than before, which can
cause web-exposed behavior change.

[Mads Ager (chromium), 2014/05/07 12:13:16]

Yes, I completely agree and I did think about that. We need to continue working
on making the dispose call that is currently happening in detach unnecessary.

-}
-#else
 inline void TreeScope::removedLastRefToScope()
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!deletionHasBegun());
@@ -2407,7 +2400,6 @@ inline void TreeScope::removedLastRefToScope()
         delete this;
     }
 }
-#endif
 
 // It's important not to inline removedLastRef, because we don't want to inline the code to
 // delete a Node at each deref call site.
@@ -2421,13 +2413,12 @@ void Node::removedLastRef()
         return;
     }
 
-#if !ENABLE(OILPAN)
 #if SECURITY_ASSERT_ENABLED
     m_deletionHasBegun = true;
 #endif
     delete this;
-#endif
 }
+#endif
 
 unsigned Node::connectedSubframeCount() const
 {
@@ -2571,6 +2562,9 @@ void Node::setCustomElementState(CustomElementState newState)
 
 void Node::trace(Visitor* visitor)
 {
+    visitor->trace(m_parentOrShadowHostNode);
+    visitor->trace(m_previous);
+    visitor->trace(m_next);
     visitor->trace(m_treeScope);
 }