Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/modules/worklet/Worklet.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef Worklet_h
 #define Worklet_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "modules/worklet/WorkletGlobalScope.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class ExecutionContext;
 
 class Worklet final : public GarbageCollectedFinalized<Worklet>, public ScriptWrappable {
     WTF_MAKE_NONCOPYABLE(Worklet);
     DEFINE_WRAPPERTYPEINFO();
 public:
     // The ExecutionContext argument is the parent document of the Worklet. The
     // Worklet inherits the url and userAgent, from the document.
     static Worklet* create(ExecutionContext*);
 
     DECLARE_TRACE();
 
 private:
     explicit Worklet(ExecutionContext*);
 
-    RefPtrWillBeMember<WorkletGlobalScope> m_workletGlobalScope;
+    Member<WorkletGlobalScope> m_workletGlobalScope;
 };
 
 } // namespace blink
 
 #endif // Worklet_h