Prepare SVGDocumentExtensions::m_elementDependencies for oilpan

Source/core/svg/SVGDocumentExtensions.h

Index: Source/core/svg/SVGDocumentExtensions.h
diff --git a/Source/core/svg/SVGDocumentExtensions.h b/Source/core/svg/SVGDocumentExtensions.h
index 1ceb7ab3a494f38a1df08d364f82a5d0e12ebb9a..5dac842d1b00b776973cc1a94b69ddc7f5788716 100644
--- a/Source/core/svg/SVGDocumentExtensions.h
+++ b/Source/core/svg/SVGDocumentExtensions.h
@@ -42,6 +42,8 @@ class SVGSMILElement;
 class SVGSVGElement;
 class Element;
 
+typedef WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> > WeakSVGElementSet;
+
 class SVGDocumentExtensions : public NoBaseWillBeGarbageCollectedFinalized<SVGDocumentExtensions> {
     WTF_MAKE_NONCOPYABLE(SVGDocumentExtensions); WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
 public:
@@ -67,7 +69,7 @@ public:
 
     SVGResourcesCache* resourcesCache() const { return m_resourcesCache.get(); }
 
-    HashSet<SVGElement*>* setOfElementsReferencingTarget(SVGElement* referencedElement) const;
+    WeakSVGElementSet* setOfElementsReferencingTarget(SVGElement* referencedElement) const;
     void addElementReferencingTarget(SVGElement* referencingElement, SVGElement* referencedElement);
     void removeAllTargetReferencesForElement(SVGElement*);
     void rebuildAllElementReferencesForTarget(SVGElement*);
@@ -98,7 +100,7 @@ public:
     void trace(Visitor*);
 
 private:
-    Document* m_document; // weak reference
+    RawPtrWillBeMember<Document> m_document;
     WillBeHeapHashSet<RawPtrWillBeMember<SVGSVGElement> > m_timeContainers; // For SVG 1.2 support this will need to be made more general.
 #if ENABLE(SVG_FONTS)
     WillBeHeapHashSet<RawPtrWillBeMember<SVGFontFaceElement> > m_svgFontFaceElements;
@@ -108,8 +110,11 @@ private:
     HashMap<AtomicString, RenderSVGResourceContainer*> m_resources;
     HashMap<AtomicString, OwnPtr<SVGPendingElements> > m_pendingResources; // Resources that are pending.
     HashMap<AtomicString, OwnPtr<SVGPendingElements> > m_pendingResourcesForRemoval; // Resources that are pending and scheduled for removal.
-    HashMap<SVGElement*, OwnPtr<HashSet<SVGElement*> > > m_elementDependencies;
+    typedef WillBeHeapHashMap<RawPtrWillBeWeakMember<SVGElement>, OwnPtrWillBeMember<WeakSVGElementSet> > ElementDependenciesMap;

[haraken, 2014/06/09 09:33:58]

Erik: If the WeakSVGElementSet becomes empty, will the entry from a
WeakMember<SVGElement> to the Member<WeakSVGElementSet> be removed from the map
by default weak processing? Otherwise, this CL is wrong, because empty
WeakSVGElementSets will be left in the map.

(Either way I think we need to land Erik's CL first:
https://codereview.chromium.org/319593004/)

+    OwnPtrWillBeMember<ElementDependenciesMap> m_elementDependencies;
     OwnPtr<SVGResourcesCache> m_resourcesCache;
+
+    // FIXME: Oilpan: make below HeapHashSet<WeakMember<SVGSVGElement> >
     HashSet<SVGSVGElement*> m_relativeLengthSVGRoots; // Root SVG elements with relative length descendants.
     FloatPoint m_translate;
 #if !ASSERT_DISABLED