Remove ResourceFetcher's access to a real FetchContext at frame detach time

Source/core/fetch/ImageResourceTest.cpp

 /*
  * Copyright (c) 2013, 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 113 matching lines @@
     ASSERT_EQ(cachedImage->image()->height(), 1);
     ASSERT_EQ(client.imageChangedCount(), 2);
     ASSERT_TRUE(client.notifyFinishedCalled());
 }
 
 TEST(ImageResourceTest, CancelOnDetach)
 {
     KURL testURL(ParsedURLString, "http://www.test.com/cancelTest.html");
     URLTestHelpers::registerMockedURLLoad(testURL, "cancelTest.html", "text/html");
 
-    RefPtrWillBeRawPtr<ResourceFetcher> fetcher = ResourceFetcher::create(FetchContext::create());
+    RefPtrWillBeRawPtr<ResourceFetcher> fetcher = ResourceFetcher::create(nullptr);
 
     // Emulate starting a real load.
     ResourcePtr<ImageResource> cachedImage = new ImageResource(ResourceRequest(testURL));
     cachedImage->setIdentifier(createUniqueIdentifier());
 
     cachedImage->load(fetcher.get(), ResourceLoaderOptions());
     memoryCache()->add(cachedImage.get());
 
     MockImageResourceClient client;
     cachedImage->addClient(&client);
@@ skipping 66 matching lines @@
     ASSERT_FALSE(cachedImage->image()->isNull());
     ASSERT_EQ(client.imageChangedCount(), 1);
     ASSERT_TRUE(client.notifyFinishedCalled());
 
     HashSet<ImageResource*> bitmapImages;
     ASSERT_TRUE(cachedImage->image()->isBitmapImage());
     bitmapImages.add(cachedImage.get());
 }
 
 } // namespace