Oilpan: fix build after r351269.

third_party/WebKit/Source/core/inspector/v8/V8AsyncCallTracker.h

 // Copyright 2014 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 V8AsyncCallTracker_h
 #define V8AsyncCallTracker_h
 
 #include "bindings/core/v8/ScriptState.h"
 #include "core/inspector/v8/V8DebuggerAgentImpl.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
 
 class ScriptState;
 
 class V8AsyncCallTracker final : public NoBaseWillBeGarbageCollectedFinalized<V8AsyncCallTracker>, public ScriptState::Observer {
     WTF_MAKE_NONCOPYABLE(V8AsyncCallTracker);
-    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(V8AsyncCallTracker);
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(V8AsyncCallTracker);
 public:
     static PassOwnPtrWillBeRawPtr<V8AsyncCallTracker> create(V8DebuggerAgentImpl* debuggerAgent)
     {
         return adoptPtrWillBeNoop(new V8AsyncCallTracker(debuggerAgent));
     }
 
     ~V8AsyncCallTracker();
     DECLARE_TRACE();
 
     void asyncCallTrackingStateChanged(bool tracking);
     void resetAsyncOperations();
 
     void didReceiveV8AsyncTaskEvent(ScriptState*, const String& eventType, const String& eventName, int id);
 
     // ScriptState::Observer implementation:
     void willDisposeScriptState(ScriptState*) override;
 
 private:
     explicit V8AsyncCallTracker(V8DebuggerAgentImpl*);
 
     void didEnqueueV8AsyncTask(ScriptState*, const String& eventName, int id);
     void willHandleV8AsyncTask(ScriptState*, const String& eventName, int id);
 
     class V8ContextAsyncOperations;
     WillBeHeapHashMap<RefPtr<ScriptState>, OwnPtrWillBeMember<V8ContextAsyncOperations>> m_contextAsyncOperationMap;
-    RawPtrWillBeMember<V8DebuggerAgentImpl> m_debuggerAgent;
+    V8DebuggerAgentImpl* m_debuggerAgent;
 };
 
 } // namespace blink
 
 #endif // V8AsyncCallTracker_h