Oilpan: fix build after r355578.

third_party/WebKit/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/Animation.h"
 #include "core/animation/AnimationEffect.h"
@@ skipping 387 matching lines @@
 {
     if (referenceTimeline().playbackRate() == 0)
         return animation.startTime() + referenceTimeline().currentTime() - animation.timeline()->currentTime();
     return animation.startTime() + (animation.timeline()->zeroTime() - referenceTimeline().zeroTime()) * 1000 * referenceTimeline().playbackRate();
 }
 
 DEFINE_TRACE(InspectorAnimationAgent)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_domAgent);
+    visitor->trace(m_cssAgent);
     visitor->trace(m_injectedScriptManager);
     visitor->trace(m_idToAnimation);
     visitor->trace(m_idToAnimationType);
     visitor->trace(m_idToAnimationClone);
 #endif
     InspectorBaseAgent::trace(visitor);
 }
 
 }