Prepare SVGSMILElement for oilpan

Source/core/svg/animation/SVGSMILElement.h

Index: Source/core/svg/animation/SVGSMILElement.h
diff --git a/Source/core/svg/animation/SVGSMILElement.h b/Source/core/svg/animation/SVGSMILElement.h
index 53ebec950bebd863e9a9c4dde21b276e9636d607..1056ddf2a3e4b3514e61f89137337584707d188e 100644
--- a/Source/core/svg/animation/SVGSMILElement.h
+++ b/Source/core/svg/animation/SVGSMILElement.h
@@ -186,8 +186,8 @@ private:
         String name() const { return m_name; }
         SMILTime offset() const { return m_offset; }
         int repeat() const { return m_repeat; }
-        Element* syncBase() const { return m_syncBase.get(); }
-        void setSyncBase(Element* element) { m_syncBase = element; }
+        SVGSMILElement* syncBase() const { return m_syncBase.get(); }
+        void setSyncBase(SVGSMILElement* element) { m_syncBase = element; }
         ConditionEventListener* eventListener() const { return m_eventListener.get(); }
         void setEventListener(PassRefPtr<ConditionEventListener>);
 
@@ -198,7 +198,7 @@ private:
         String m_name;
         SMILTime m_offset;
         int m_repeat;
-        RefPtrWillBeMember<Element> m_syncBase;
+        RefPtrWillBeWeakMember<SVGSMILElement> m_syncBase;

[haraken, 2014/05/29 04:58:58]

It looks strange that RefPtr becomes WeakMember. Shouldn't the Condition and the
SVGSMILElement live & die together? In what situation do we want to let the
Condition outlive the SVGSMILElement?

[kouhei (in TOK), 2014/05/29 05:08:10]

syncBase was manually unregistered via d-tor, however we are removing this in
oilpan builds, so this need to be weak.

[haraken, 2014/05/29 06:14:10]

Even if "X was manually unregistered via d-tor", it doesn't necessarily mean
that we want to make it weak. It's possible that the pointer was a back pointer
(not a weak pointer) and thus was manually unregistered when X died.

The point is whether the Condition and the SVGSMILElement should die together or
not. So I want to understand in what situation we want to let the Condition
outlive the SVGSMILElement.

         RefPtr<ConditionEventListener> m_eventListener;
     };
     bool parseCondition(const String&, BeginOrEnd beginOrEnd);
@@ -236,7 +236,7 @@ private:
 
     bool m_isWaitingForFirstInterval;
 
-    typedef WillBeHeapHashSet<RawPtrWillBeMember<SVGSMILElement> > TimeDependentSet;
+    typedef WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGSMILElement> > TimeDependentSet;
     TimeDependentSet m_syncBaseDependents;
 
     // Instance time lists