Oilpan: fix build after r192098.

Source/core/inspector/InspectorOverlayImpl.cpp

 /*
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 96 matching lines @@
 }
 
 DEFINE_TRACE(InspectorOverlayImpl)
 {
     visitor->trace(m_page);
     visitor->trace(m_highlightNode);
     visitor->trace(m_eventTargetNode);
     visitor->trace(m_overlayPage);
     visitor->trace(m_overlayHost);
     visitor->trace(m_listener);
+    InspectorOverlay::trace(visitor);
 }
 
 void InspectorOverlayImpl::paint(GraphicsContext& context)
 {
     if (isEmpty())
         return;
     FrameView* view = toLocalFrame(overlayPage()->mainFrame())->view();
     ASSERT(!view->needsLayout());
     view->paint(&context, IntRect(0, 0, view->width(), view->height()));
 }
@@ skipping 306 matching lines @@
     if (!m_suspendCount++)
         freePage();
 }
 
 void InspectorOverlayImpl::resumeUpdates()
 {
     --m_suspendCount;
 }
 
 } // namespace blink