Revert of Split the code for fetching images and for decoding images into two separate classes.

components/image_fetcher/image_data_fetcher.h

-// Copyright 2016 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 COMPONENTS_IMAGE_FETCHER_IMAGE_DATA_FETCHER_H_
-#define COMPONENTS_IMAGE_FETCHER_IMAGE_DATA_FETCHER_H_
-
-#include <map>
-#include <memory>
-#include <string>
-
-#include "base/callback.h"
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "url/gurl.h"
-
-namespace net {
-class URLRequestContextGetter;
-}  // namespace net
-
-namespace image_fetcher {
-
-class ImageDataFetcher {
- public:
-  using ImageDataFetcherCallback =
-      base::Callback<void(const std::string& image_data)>;
-
-  explicit ImageDataFetcher(
-      net::URLRequestContextGetter* url_request_context_getter);
-  ~ImageDataFetcher();
-
-  // Fetches the raw image bytes from the given |image_url| and calls the given
-  // |callback|. The callback is run even if fetching the URL fails. In case
-  // of an error an empty string is passed to the callback.
-  void FetchImageData(const GURL& image_url,
-                      const ImageDataFetcherCallback& callback);
-
- private:
-  class ImageDataFetcherRequest;
-
-  // Removes the ImageDataFetcherRequest for the given |image_url| from the
-  // internal request queue.
-  void RemoveImageDataFetcherRequest(const GURL& image_url);
-
-  // All active image url requests.
-  std::map<const GURL, std::unique_ptr<ImageDataFetcherRequest>>
-      pending_requests_;
-
-  scoped_refptr<net::URLRequestContextGetter> url_request_context_getter_;
-
-  DISALLOW_COPY_AND_ASSIGN(ImageDataFetcher);
-};
-
-}  // namespace image_fetcher
-
-#endif  // COMPONENTS_IMAGE_FETCHER_IMAGE_DATA_FETCHER_H_