Reland "Move MemoryCache implementation details out of Resource"

Source/core/fetch/ImageResource.cpp

Index: Source/core/fetch/ImageResource.cpp
diff --git a/Source/core/fetch/ImageResource.cpp b/Source/core/fetch/ImageResource.cpp
index 5b8e226924158cf5b45f8baec16f7e0517b042e5..9e8cce3af46e6e387d5dcdad456656e32bb10502 100644
--- a/Source/core/fetch/ImageResource.cpp
+++ b/Source/core/fetch/ImageResource.cpp
@@ -61,6 +61,15 @@ ImageResource::ImageResource(WebCore::Image* image)
     setCustomAcceptHeader();
 }
 
+ImageResource::ImageResource(const ResourceRequest& resourceRequest, WebCore::Image* image)
+    : Resource(resourceRequest, Image)
+    , m_image(image)
+{
+    setStatus(Cached);
+    setLoading(false);
+    setCustomAcceptHeader();
+}
+
 ImageResource::~ImageResource()
 {
     clearImage();