Oilpan: LinkLoaderClient must be a GC mixin.

third_party/WebKit/Source/core/loader/LinkLoader.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:
  *
  *     * 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 307 matching lines @@
     // Only prerenders need treatment here; other links either use the Resource interface, or are notionally
     // atomic (dns prefetch).
     if (m_prerender) {
         m_prerender->cancel();
         m_prerender.clear();
     }
 }
 
 DEFINE_TRACE(LinkLoader)
 {
+    visitor->trace(m_client);
     visitor->trace(m_prerender);
     visitor->trace(m_linkPreloadResourceClient);
     ResourceOwner<Resource, ResourceClient>::trace(visitor);
 }
 
 }