Oilpan: Fix SVGElement leaks introduced in 201698

Source/core/svg/properties/SVGAnimatedProperty.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
 G*     * Redistributions in binary form must reproduce the above
@@ skipping 74 matching lines @@
 
     void setReadOnly()
     {
         m_isReadOnly = true;
     }
 
     bool isSpecified() const;
 
     DEFINE_INLINE_VIRTUAL_TRACE()
     {
-        visitor->trace(m_contextElement);
     }
 
 protected:
     SVGAnimatedPropertyBase(AnimatedPropertyType, SVGElement*, const QualifiedName& attributeName);
 
 private:
     const AnimatedPropertyType m_type;
     bool m_isReadOnly;
 
     // This reference is kept alive from V8 wrapper
-    RawPtrWillBeMember<SVGElement> m_contextElement;
+    // TODO(oilpan): This should be a Member. Currently we cannot do it because
+    // it creates a cycle as follows:
+    // SVGInterporation =(Persistent)=>
+    // SVGAnimatedProperty =(Member)=>
+    // SVGElement =(Member)=>
+    // ElementRareData =(Member)=>
+    // ElementAnimations =(part of object)=>
+    // CSSAnimations =(part of object)=>
+    // CSSAnimationUpdate =(Member)=>
+    // NewTransition =(Member)=>
+    // InertEffect =(Member)=>
+    // EffectModel =(RefPtr)=>
+    // InterpolationEffect =(RefPtr)=>
+    // InterpolationRecord =(RefPtr)=>
+    // SVGInterpolation
+    SVGElement* m_contextElement;

[sof, 2015/09/04 07:16:49]

Add a GC_PLUGIN_IGNORE() (and a tracking issue, if you want to) ?

[haraken, 2015/09/04 07:18:03]

Will do in a follow-up (to fix the leak in oilpan build asap).

 
     const QualifiedName& m_attributeName;
 };
 
 template <typename Property>
 class SVGAnimatedPropertyCommon : public SVGAnimatedPropertyBase {
 public:
     Property* baseValue()
     {
         return m_baseValue.get();
@@ skipping 204 matching lines @@
     // When animated:
     //     m_animValTearOff targets m_currentValue.
     //     m_baseValTearOff targets m_baseValue.
     RefPtrWillBeMember<TearOffType> m_baseValTearOff;
     RefPtrWillBeMember<TearOffType> m_animValTearOff;
 };
 
 } // namespace blink
 
 #endif // SVGAnimatedProperty_h