Oilpan: ImageObserver needs to be a GC mixin.

third_party/WebKit/Source/core/fetch/ImageResource.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 76 matching lines @@
 {
     WTF_LOG(Timers, "new ImageResource(ResourceRequest, Image) %p", this);
     setStatus(Cached);
     setLoading(false);
     setCustomAcceptHeader();
 }
 
 ImageResource::~ImageResource()
 {
     WTF_LOG(Timers, "~ImageResource %p", this);
     clearImage();

[haraken, 2016/01/20 23:24:27]

Can we remove this in oilpan?

[sof, 2016/01/21 06:14:24]

Certainly can; well spotted. Removed, but leaving behind a comment.

 }
 
+DEFINE_TRACE(ImageResource)
+{
+    Resource::trace(visitor);
+    ImageObserver::trace(visitor);
+}
+
 void ImageResource::load(ResourceFetcher* fetcher, const ResourceLoaderOptions& options)
 {
     if (!fetcher || fetcher->autoLoadImages())
         Resource::load(fetcher, options);
     else
         setLoading(false);
 }
 
 void ImageResource::didAddClient(ResourceClient* c)
 {
@@ skipping 344 matching lines @@
         return true;
     return !securityOrigin->taintsCanvas(response().url());
 }
 
 bool ImageResource::loadingMultipartContent() const
 {
     return m_loader && m_loader->loadingMultipartContent();
 }
 
 } // namespace blink