Oilpan: build fix after r183847

Source/core/inspector/InspectorAnimationAgent.cpp

 // 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.
 
 #include "config.h"
 
 #include "core/inspector/InspectorAnimationAgent.h"
 
 #include "core/animation/AnimationNode.h"
 #include "core/animation/AnimationPlayer.h"
@@ skipping 116 matching lines @@
         .setFillMode(animationNode.specifiedTiming().fillMode)
         .setTimeFraction(animationNode.timeFraction())
         .setName(animationNode.name());
     return animationObject.release();
 }
 
 void InspectorAnimationAgent::trace(Visitor* visitor)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_idToAnimationPlayer);
+    visitor->trace(m_domAgent);
 #endif
     InspectorBaseAgent::trace(visitor);
 }
 
 }