Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/modules/remoteplayback/RemotePlaybackAvailability.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 RemotePlaybackAvailability_h
 #define RemotePlaybackAvailability_h
 
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/events/EventTarget.h"
 
 namespace blink {
 
 class ExecutionContext;
 class ScriptPromiseResolver;
 
 // Expose whether there is a remote playback device available for a media
 // element. The object will be initialized with a default value passed via
 // ::take() and will then listen to availability changes.
 class RemotePlaybackAvailability final : public RefCountedGarbageCollectedEventTargetWithInlineData<RemotePlaybackAvailability>, public ContextLifecycleObserver {
     REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(RemotePlaybackAvailability);
     DEFINE_WRAPPERTYPEINFO();
-    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(RemotePlaybackAvailability);
+    USING_GARBAGE_COLLECTED_MIXIN(RemotePlaybackAvailability);
 public:
     static RemotePlaybackAvailability* take(ScriptPromiseResolver*, bool);
     ~RemotePlaybackAvailability() override;
 
     // EventTarget implementation.
     const AtomicString& interfaceName() const override;
     ExecutionContext* getExecutionContext() const override;
 
     void availabilityChanged(bool);
 
     bool value() const;
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(change);
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     RemotePlaybackAvailability(ExecutionContext*, bool);
 
     bool m_value;
 };
 
 } // namespace blink
 
 #endif // RemotePlaybackAvailability_h