Oilpan: add missing tracing of InspectorTracingAgent objects.

Source/core/inspector/InspectorTracingAgent.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 InspectorTracingAgent_h
 #define InspectorTracingAgent_h
 
 #include "core/InspectorFrontend.h"
@@ skipping 10 matching lines @@
 class InspectorTracingAgent final
     : public InspectorBaseAgent<InspectorTracingAgent>
     , public InspectorBackendDispatcher::TracingCommandHandler {
     WTF_MAKE_NONCOPYABLE(InspectorTracingAgent);
 public:
     static PassOwnPtrWillBeRawPtr<InspectorTracingAgent> create(InspectorClient* client, InspectorWorkerAgent* workerAgent, Page* page)
     {
         return adoptPtrWillBeNoop(new InspectorTracingAgent(client, workerAgent, page));
     }
 
+    void trace(Visitor*) override;
+
     // Base agent methods.
     virtual void restore() override;
     virtual void setFrontend(InspectorFrontend*) override;
     virtual void clearFrontend() override;
 
     // Protocol method implementations.
     virtual void start(ErrorString*, const String* categoryFilter, const String*, const double*, PassRefPtrWillBeRawPtr<StartCallback>) override;
     virtual void end(ErrorString*, PassRefPtrWillBeRawPtr<EndCallback>);
 
     // Methods for other agents to use.
     void setLayerTreeId(int);
 
 private:
     InspectorTracingAgent(InspectorClient*, InspectorWorkerAgent*, Page*);
 
     void emitMetadataEvents();
     void resetSessionId();
     String sessionId();
 
     int m_layerTreeId;
     InspectorClient* m_client;
     InspectorFrontend::Tracing* m_frontend;
-    InspectorWorkerAgent* m_workerAgent;
-    Page* m_page;
+    RawPtrWillBeMember<InspectorWorkerAgent> m_workerAgent;
+    RawPtrWillBeMember<Page> m_page;
 };
 
-}
+} // namespace blink
 
 #endif // InspectorTracingAgent_h