Create the IOSImageDataFetcher

components/image_fetcher/ios/ios_image_data_fetcher.h

Index: components/image_fetcher/ios/ios_image_data_fetcher.h
diff --git a/components/image_fetcher/ios/ios_image_data_fetcher.h b/components/image_fetcher/ios/ios_image_data_fetcher.h
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+// Copyright 2017 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_IOS_IOS_IMAGE_DATA_FETCHER_H_
+#define COMPONENTS_IMAGE_FETCHER_IOS_IOS_IMAGE_DATA_FETCHER_H_
+
+#import <Foundation/Foundation.h>
+
+#include "base/memory/ref_counted.h"
+#include "components/data_use_measurement/core/data_use_user_data.h"
+
+namespace base {
+class TaskRunner;
+}
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace image_fetcher {
+class ImageDataFetcher;
+}
+
+class GURL;
+
+namespace image_fetcher {
+
+// Callback that informs of the download of an image encoded in |data|.
+using IOSImageDataFetcherCallback = void (^)(int http_response_code,
+                                             NSData* data);
+
+class IOSImageDataFetcher {
+ public:
+  using DataUseServiceName = data_use_measurement::DataUseUserData::ServiceName;
+
+  // The TaskRunner is used to eventually decode the image.
+  IOSImageDataFetcher(net::URLRequestContextGetter* url_request_context_getter,
+                      const scoped_refptr<base::TaskRunner>& task_runner);
+  virtual ~IOSImageDataFetcher();
+
+  // Start downloading the image at the given |image_url|. The |callback| will
+  // be called with the downloaded image, or nil if any error happened or the
+  // http response header is not HTTP_OK (200). If the url is a data URL, the
+  // http response header is considered to be HTTP_OK.
+  void FetchImageDataWebpDecoded(const GURL& image_url,
+                                 IOSImageDataFetcherCallback callback);
+
+  // Sets a service name against which to track data usage.
+  void SetDataUseServiceName(DataUseServiceName data_use_service_name);
+
+ private:
+  // The task runner used to decode images if necessary.
+  const scoped_refptr<base::TaskRunner> task_runner_;
+  std::unique_ptr<ImageDataFetcher> image_data_fetcher_;
+};
+}  // namespace image_fetcher
+
+#endif  // COMPONENTS_IMAGE_FETCHER_IOS_IOS_IMAGE_DATA_FETCHER_H_