Split FaviconHelper in two: ImageLoadingHelper and FaviconHelper

content/renderer/image_loading_helper.h

Index: content/renderer/image_loading_helper.h
diff --git a/content/renderer/image_loading_helper.h b/content/renderer/image_loading_helper.h
new file mode 100644
index 0000000000000000000000000000000000000000..961265a97f8935c603f6f3384d9f8044f60a47b4
--- /dev/null
+++ b/content/renderer/image_loading_helper.h
@@ -0,0 +1,70 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_RENDERER_IMAGE_LOADING_HELPER_H_
+#define CONTENT_RENDERER_IMAGE_LOADING_HELPER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/memory/scoped_vector.h"
+#include "content/public/renderer/render_view_observer.h"
+#include "googleurl/src/gurl.h"
+
+class SkBitmap;
+
+namespace webkit_glue {
+class MultiResolutionImageResourceFetcher;
+}
+
+namespace content {
+
+// This class deals with favicon downloading.
+// One instance of ImageLoadingHelper is owned by RenderView.
+class ImageLoadingHelper : public RenderViewObserver {
+ public:
+  explicit ImageLoadingHelper(RenderView* render_view);
+
+ private:
+  virtual ~ImageLoadingHelper();
+
+  // Message handler.
+  void OnDownloadImage(int id, const GURL& image_url, int image_size);
+
+  // Requests to download an image. When done, the ImageLoadingHelper
+  // is notified by way of DidDownloadImage. Returns true if the
+  // request was successfully started, false otherwise. id is used to
+  // uniquely identify the request and passed back to the
+  // DidDownloadImage method. If the image has multiple frames, the
+  // frame whose size is image_size is returned. If the image doesn't
+  // have a frame at the specified size, the first is returned.
+  bool DownloadImage(int id, const GURL& image_url, int image_size);
+
+  // This callback is triggered when DownloadImage completes, either
+  // succesfully or with a failure. See DownloadImage for more
+  // details.
+  void DidDownloadImage(
+      int requested_size,
+      webkit_glue::MultiResolutionImageResourceFetcher* fetcher,
+      const std::vector<SkBitmap>& images);
+
+  // Decodes a data: URL image or returns an empty image in case of failure.
+  SkBitmap ImageFromDataUrl(const GURL&) const;
+
+  // RenderViewObserver implementation.
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  typedef ScopedVector<webkit_glue::MultiResolutionImageResourceFetcher>
+    ImageResourceFetcherList;
+
+  // ImageResourceFetchers schedule via DownloadImage.
+  ImageResourceFetcherList image_fetchers_;
+
+  DISALLOW_COPY_AND_ASSIGN(ImageLoadingHelper);
+};
+
+} // namespace content
+
+#endif  // CONTENT_RENDERER_IMAGE_LOADING_HELPER_H_
+