Oilpan: add [WillBeGarbageCollected] for Node.

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 d15908211b4b57fcda2a9368ec2579faf56e2dfc..9d849bb4146e69551d11e1a0f9ec82f151d114ea 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -925,13 +925,13 @@ bool Document::importContainerNodeChildren(ContainerNode* oldContainerNode, Pass
     return true;
 }
 
-PassRefPtr<Node> Document::importNode(Node* importedNode, ExceptionState& ec)
+PassRefPtrWillBeRawPtr<Node> Document::importNode(Node* importedNode, ExceptionState& ec)
 {
     UseCounter::countDeprecation(this, UseCounter::DocumentImportNodeOptionalArgument);
     return importNode(importedNode, true, ec);
 }
 
-PassRefPtr<Node> Document::importNode(Node* importedNode, bool deep, ExceptionState& exceptionState)
+PassRefPtrWillBeRawPtr<Node> Document::importNode(Node* importedNode, bool deep, ExceptionState& exceptionState)
 {
     if (!importedNode) {
         exceptionState.throwDOMException(NotSupportedError, ExceptionMessages::argumentNullOrIncorrectType(1, "Node"));
@@ -5745,6 +5745,14 @@ void Document::clearWeakMembers(Visitor* visitor)
         for (unsigned i = 0; i < deadNodes.size(); ++i)
             didClearTouchEventHandlers(deadNodes[i]);
     }
+    if (m_domWindow && !visitor->isAlive(m_domWindow)) {
+        ASSERT(isDisposed());

[Mads Ager (chromium), 2014/05/26 06:15:20]

This seems fishy to me. If the Document is dead and the DOMWindow is still alive
they must have been explicitly disassociated. The Document must have been
detached. When a document is detached it is no longer displayed and it seems
surprising that we would need touch event handlers for something that is not
even displayed? A Document cannot be reattached. Can't we clear the touch event
handlers at that point instead of doing it via weak processing? Do we ever need
the touch event handlers after a document has been explicitly detached?

I would expect DOMWindow and Document to have strong pointers to each other as
long as they are associated. When the document is detached from a DOMWindow we
should perform cleanup. If it is never detached, the DOMWindow and the Document
should die together and no cleanup is needed? 

+        // Oilpan: this mirrors the clearing of the document object's touch
+        // handlers that happen when the DOMWindow is destructed in a non-Oilpan
+        // setting (done via DOMWindow::removeAllEventListeners().)
+        didClearTouchEventHandlers(this);
+        m_domWindow.clear();
+    }
 }
 
 void Document::trace(Visitor* visitor)