Use RefPtr for MutationObserver in MutationObserverInterestGroup.

third_party/WebKit/Source/core/dom/MutationObserverInterestGroup.cpp

Index: third_party/WebKit/Source/core/dom/MutationObserverInterestGroup.cpp
diff --git a/third_party/WebKit/Source/core/dom/MutationObserverInterestGroup.cpp b/third_party/WebKit/Source/core/dom/MutationObserverInterestGroup.cpp
index 689d0f4466328615c24dabccf1b453df224db152..26e0a7e0bca99000af3a4c38442ccc6911b5e29a 100644
--- a/third_party/WebKit/Source/core/dom/MutationObserverInterestGroup.cpp
+++ b/third_party/WebKit/Source/core/dom/MutationObserverInterestGroup.cpp
@@ -39,7 +39,7 @@ namespace blink {
 PassOwnPtrWillBeRawPtr<MutationObserverInterestGroup> MutationObserverInterestGroup::createIfNeeded(Node& target, MutationObserver::MutationType type, MutationRecordDeliveryOptions oldValueFlag, const QualifiedName* attributeName)
 {
     ASSERT((type == MutationObserver::Attributes && attributeName) || !attributeName);
-    WillBeHeapHashMap<RawPtrWillBeMember<MutationObserver>, MutationRecordDeliveryOptions> observers;
+    WillBeHeapHashMap<RefPtrWillBeMember<MutationObserver>, MutationRecordDeliveryOptions> observers;
     target.getRegisteredMutationObserversOfType(observers, type, attributeName);
     if (observers.isEmpty())
         return nullptr;
@@ -47,7 +47,7 @@ PassOwnPtrWillBeRawPtr<MutationObserverInterestGroup> MutationObserverInterestGr
     return adoptPtrWillBeNoop(new MutationObserverInterestGroup(observers, oldValueFlag));
 }
 
-MutationObserverInterestGroup::MutationObserverInterestGroup(WillBeHeapHashMap<RawPtrWillBeMember<MutationObserver>, MutationRecordDeliveryOptions>& observers, MutationRecordDeliveryOptions oldValueFlag)
+MutationObserverInterestGroup::MutationObserverInterestGroup(WillBeHeapHashMap<RefPtrWillBeMember<MutationObserver>, MutationRecordDeliveryOptions>& observers, MutationRecordDeliveryOptions oldValueFlag)
     : m_oldValueFlag(oldValueFlag)
 {
     ASSERT(!observers.isEmpty());
@@ -68,7 +68,7 @@ void MutationObserverInterestGroup::enqueueMutationRecord(PassRefPtrWillBeRawPtr
     RefPtrWillBeRawPtr<MutationRecord> mutation = prpMutation;
     RefPtrWillBeRawPtr<MutationRecord> mutationWithNullOldValue = nullptr;
     for (auto& iter : m_observers) {
-        MutationObserver* observer = iter.key;
+        MutationObserver* observer = iter.key.get();
         if (hasOldValue(iter.value)) {
             observer->enqueueMutationRecord(mutation);
             continue;