Oilpan: cleanup based on review comments after removal of TreeShared.

Source/core/svg/SVGElement.cpp

Index: Source/core/svg/SVGElement.cpp
diff --git a/Source/core/svg/SVGElement.cpp b/Source/core/svg/SVGElement.cpp
index 254df4ec29e49a72ccb6c87193e4a04448401e6a..ca65b9030feea5cedc54dbe65d0b6b386d9af307 100644
--- a/Source/core/svg/SVGElement.cpp
+++ b/Source/core/svg/SVGElement.cpp
@@ -532,7 +532,7 @@ void SVGElement::mapInstanceToElement(SVGElementInstance* instance)
 {
     ASSERT(instance);
 
-    HashSet<SVGElement*>& instances = ensureSVGRareData()->elementInstances();
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >& instances = ensureSVGRareData()->elementInstances();
     ASSERT(!instances.contains(instance->shadowTreeElement()));
 
     instances.add(instance->shadowTreeElement());
@@ -546,18 +546,27 @@ void SVGElement::removeInstanceMapping(SVGElementInstance* instance)
     if (!instance->shadowTreeElement())
         return;
 
-    HashSet<SVGElement*>& instances = svgRareData()->elementInstances();
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >& instances = svgRareData()->elementInstances();

[haraken, 2014/05/07 12:50:20]

Shall we typedef this? We have a lot of 
WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> > in this CL.

[Mads Ager (chromium), 2014/05/08 09:08:59]

The issue is that this type is used all over the place and there seems to be no
good place for the typedef...

[haraken, 2014/05/08 09:15:41]

Probably you can define it in SVGElement.h, since the call sites of
WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> > should include
SVGElement.h. If no, I'm OK with not having the typedef.

     ASSERT(instances.contains(instance->shadowTreeElement()));
 
     instances.remove(instance->shadowTreeElement());
 }
 
-const HashSet<SVGElement*>& SVGElement::instancesForElement() const
+static WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >& emptyInstances()
 {
-    if (!hasSVGRareData()) {
-        DEFINE_STATIC_LOCAL(HashSet<SVGElement*>, emptyInstances, ());
-        return emptyInstances;
-    }
+#if ENABLE(OILPAN)
+    DEFINE_STATIC_LOCAL(Persistent<HeapHashSet<WeakMember<SVGElement> > >, emptyInstances, (new HeapHashSet<WeakMember<SVGElement> >));
+    return *emptyInstances;
+#else
+    DEFINE_STATIC_LOCAL(HashSet<RawPtr<SVGElement> >, emptyInstances, ());
+    return emptyInstances;
+#endif
+}
+
+const WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >& SVGElement::instancesForElement() const
+{
+    if (!hasSVGRareData())
+        return emptyInstances();
     return svgRareData()->elementInstances();

[haraken, 2014/05/07 12:50:20]

Probably not related to your CL, but I'm not quite sure how this works.

If we don't have SVGRareData, we return a hash set from emptyInstances(). Then
we add things to the hash set. At some point, SVGRareData is created, then we
return a hash set from the SVGRareData. Now we have two hash sets involved.
Won't it cause an issue?

[Mads Ager (chromium), 2014/05/08 09:08:59]

Yeah, unrelated to my change. When you collect element instance you always
create a new set, so the empty set here should never be updated. In any case, if
there is an issue here it is unrelated to this change. 

 }
 
@@ -785,7 +794,7 @@ bool SVGElement::haveLoadedRequiredResources()
     return true;
 }
 
-static inline void collectInstancesForSVGElement(SVGElement* element, HashSet<SVGElement*>& instances)
+static inline void collectInstancesForSVGElement(SVGElement* element, WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >& instances)
 {
     ASSERT(element);
     if (element->containingShadowRoot())
@@ -805,10 +814,10 @@ bool SVGElement::addEventListener(const AtomicString& eventType, PassRefPtr<Even
         return false;
 
     // Add event listener to all shadow tree DOM element instances
-    HashSet<SVGElement*> instances;
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> > instances;
     collectInstancesForSVGElement(this, instances);
-    const HashSet<SVGElement*>::const_iterator end = instances.end();
-    for (HashSet<SVGElement*>::const_iterator it = instances.begin(); it != end; ++it) {
+    const WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >::const_iterator end = instances.end();
+    for (WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >::const_iterator it = instances.begin(); it != end; ++it) {
         bool result = (*it)->Node::addEventListener(eventType, listener, useCapture);
         ASSERT_UNUSED(result, result);
     }
@@ -818,7 +827,7 @@ bool SVGElement::addEventListener(const AtomicString& eventType, PassRefPtr<Even
 
 bool SVGElement::removeEventListener(const AtomicString& eventType, EventListener* listener, bool useCapture)
 {
-    HashSet<SVGElement*> instances;
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> > instances;
     collectInstancesForSVGElement(this, instances);
     if (instances.isEmpty())
         return Node::removeEventListener(eventType, listener, useCapture);
@@ -835,8 +844,8 @@ bool SVGElement::removeEventListener(const AtomicString& eventType, EventListene
         return false;
 
     // Remove event listener from all shadow tree DOM element instances
-    const HashSet<SVGElement*>::const_iterator end = instances.end();
-    for (HashSet<SVGElement*>::const_iterator it = instances.begin(); it != end; ++it) {
+    const WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >::const_iterator end = instances.end();
+    for (WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >::const_iterator it = instances.begin(); it != end; ++it) {
         SVGElement* shadowTreeElement = *it;
         ASSERT(shadowTreeElement);
 
@@ -1041,13 +1050,13 @@ void SVGElement::invalidateInstances()
     if (instanceUpdatesBlocked())
         return;
 
-    const HashSet<SVGElement*>& set = instancesForElement();
+    const WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >& set = instancesForElement();
     if (set.isEmpty())
         return;
 
     // Mark all use elements referencing 'element' for rebuilding
-    const HashSet<SVGElement*>::const_iterator end = set.end();
-    for (HashSet<SVGElement*>::const_iterator it = set.begin(); it != end; ++it) {
+    const WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >::const_iterator end = set.end();
+    for (WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >::const_iterator it = set.begin(); it != end; ++it) {
         (*it)->setCorrespondingElement(0);
 
         if (SVGUseElement* element = (*it)->correspondingUseElement()) {