Oilpan: move mutation observers to the Oilpan heap.

Source/core/dom/MutationObserverRegistration.cpp

Index: Source/core/dom/MutationObserverRegistration.cpp
diff --git a/Source/core/dom/MutationObserverRegistration.cpp b/Source/core/dom/MutationObserverRegistration.cpp
index 2680bb73b6601eb2e57e356936c800d56c623464..b8098a260b951629a3f5801f5d5aace6e5525b46 100644
--- a/Source/core/dom/MutationObserverRegistration.cpp
+++ b/Source/core/dom/MutationObserverRegistration.cpp
@@ -37,9 +37,9 @@
 
 namespace WebCore {
 
-PassOwnPtr<MutationObserverRegistration> MutationObserverRegistration::create(MutationObserver& observer, Node& registrationNode, MutationObserverOptions options, const HashSet<AtomicString>& attributeFilter)
+PassOwnPtrWillBeRawPtr<MutationObserverRegistration> MutationObserverRegistration::create(MutationObserver& observer, Node& registrationNode, MutationObserverOptions options, const HashSet<AtomicString>& attributeFilter)
 {
-    return adoptPtr(new MutationObserverRegistration(observer, registrationNode, options, attributeFilter));
+    return adoptPtrWillBeNoop(new MutationObserverRegistration(observer, registrationNode, options, attributeFilter));
 }
 
 MutationObserverRegistration::MutationObserverRegistration(MutationObserver& observer, Node& registrationNode, MutationObserverOptions options, const HashSet<AtomicString>& attributeFilter)
@@ -53,8 +53,20 @@ MutationObserverRegistration::MutationObserverRegistration(MutationObserver& obs
 
 MutationObserverRegistration::~MutationObserverRegistration()
 {
+#if ENABLE(OILPAN)
+    // dispose() will not have been called if this assert
+    // triggers.
+    ASSERT(!m_observer);
+#else
+    dispose();
+#endif

[haraken, 2014/04/21 06:00:34]

As I commented previously, would it be possible to remove the #if branch?
Currently dispose() is called before the destructor in oilpan builds, but
dispose() is called inside the destructor. Having two call paths is not that
nice.

[sof, 2014/04/21 07:34:05]

I can remove it, but why is the assert harmful to have around?

[haraken, 2014/04/21 07:41:31]

I'm not concerned about having the assert. My point is just that if we could
reduce the number of #if ENABLE(OILPAN), it would be better :) Having multiple
call paths depending on oilpan/non-oilpan builds would make future development a
bit harder.

[sof, 2014/04/21 12:45:16]

ok, I've switched to explicit dispose()s for the non-Oilpan case also, and
dropped this #if.

+}
+
+void MutationObserverRegistration::dispose()
+{
     clearTransientRegistrations();
     m_observer->observationEnded(this);
+    m_observer.clear();

[haraken, 2014/04/21 06:00:34]

Shall we also clear m_registrationNode in dispose() and add
ASSERT(!m_registrationNode) in ~MutationObserverRegistration() ?

[sof, 2014/04/21 12:45:16]

m_registrationNode was left as a reference, as that was deemed safe by earlier
discussions.

 }
 
 void MutationObserverRegistration::resetObservation(MutationObserverOptions options, const HashSet<AtomicString>& attributeFilter)
@@ -130,4 +142,9 @@ void MutationObserverRegistration::addRegistrationNodesToSet(HashSet<Node*>& nod
         nodes.add(iter->get());
 }
 
+void MutationObserverRegistration::trace(Visitor* visitor)
+{
+    visitor->trace(m_observer);
+}
+
 } // namespace WebCore