Oilpan: fix build after r187699.

Source/core/inspector/AsyncCallStackTracker.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 131 matching lines @@
     return 0;
 }
 
 AsyncCallStackTracker::AsyncCallStackTracker(InspectorDebuggerAgent* debuggerAgent, InstrumentingAgents* instrumentingAgents)
     : m_debuggerAgent(debuggerAgent)
     , m_instrumentingAgents(instrumentingAgents)
 {
     m_debuggerAgent->addAsyncCallTrackingListener(this);
 }
 
-DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(AsyncCallStackTracker);
+AsyncCallStackTracker::~AsyncCallStackTracker()
+{
+}
 
 void AsyncCallStackTracker::asyncCallTrackingStateChanged(bool tracking)
 {
     m_instrumentingAgents->setAsyncCallStackTracker(tracking ? this : nullptr);
 }
 
 void AsyncCallStackTracker::resetAsyncCallChains()
 {
     for (auto& it : m_executionContextDataMap)
         it.value->dispose();
@@ skipping 270 matching lines @@
         data = m_executionContextDataMap.set(context, adoptPtrWillBeNoop(new AsyncCallStackTracker::ExecutionContextData(this, context)))
             .storedValue->value.get();
     }
     return data;
 }
 
 void AsyncCallStackTracker::trace(Visitor* visitor)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_executionContextDataMap);
+    visitor->trace(m_debuggerAgent);
+    visitor->trace(m_instrumentingAgents);
 #endif
+    InspectorDebuggerAgent::AsyncCallTrackingListener::trace(visitor);
 }
 
 } // namespace blink