Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/core/dom/MutationCallback.h

Index: third_party/WebKit/Source/core/dom/MutationCallback.h
diff --git a/third_party/WebKit/Source/core/dom/MutationCallback.h b/third_party/WebKit/Source/core/dom/MutationCallback.h
index 0e737c75f4ffa852e579e8850fd18e0ff2a12833..9102a4f5c62e44bb32aa8a109ca3099c04cf33aa 100644
--- a/third_party/WebKit/Source/core/dom/MutationCallback.h
+++ b/third_party/WebKit/Source/core/dom/MutationCallback.h
@@ -40,11 +40,11 @@ namespace blink {
 class MutationRecord;
 class MutationObserver;
 
-class MutationCallback : public NoBaseWillBeGarbageCollectedFinalized<MutationCallback> {
+class MutationCallback : public GarbageCollectedFinalized<MutationCallback> {
 public:
     virtual ~MutationCallback() { }
 
-    virtual void call(const WillBeHeapVector<RefPtrWillBeMember<MutationRecord>>&, MutationObserver*) = 0;
+    virtual void call(const HeapVector<Member<MutationRecord>>&, MutationObserver*) = 0;
     virtual ExecutionContext* getExecutionContext() const = 0;
 
     DEFINE_INLINE_VIRTUAL_TRACE() { }