Reland "Move MemoryCache implementation details out of Resource"

Source/core/fetch/ImageResource.h

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller <mueller@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
     version 2 of the License, or (at your option) any later version.
@@ skipping 31 matching lines @@
 class SecurityOrigin;
 
 class ImageResource FINAL : public Resource, public ImageObserver {
     friend class MemoryCache;
 
 public:
     typedef ImageResourceClient ClientType;
 
     ImageResource(const ResourceRequest&);
     ImageResource(WebCore::Image*);
+    // Exposed for testing
+    ImageResource(const ResourceRequest&, WebCore::Image*);
     virtual ~ImageResource();
 
     virtual void load(ResourceFetcher*, const ResourceLoaderOptions&) OVERRIDE;
 
     WebCore::Image* image(); // Returns the nullImage() if the image is not available yet.
     WebCore::Image* imageForRenderer(const RenderObject*); // Returns the nullImage() if the image is not available yet.
     bool hasImage() const { return m_image.get(); }
     bool currentFrameKnownToBeOpaque(const RenderObject*); // Side effect: ensures decoded image is in cache, therefore should only be called when about to draw the image.
 
     static std::pair<WebCore::Image*, float> brokenImage(float deviceScaleFactor); // Returns an image and the image's resolution scale factor.
@@ skipping 68 matching lines @@
     OwnPtr<SVGImageCache> m_svgImageCache;
     bool m_loadingMultipartContent;
     bool m_hasDevicePixelRatioHeaderValue;
 };
 
 DEFINE_RESOURCE_TYPE_CASTS(Image);
 
 }
 
 #endif