Create the IOSImageDataFetcherWrapper

components/image_fetcher/ios/ios_image_data_fetcher_wrapper.h

+// 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_WRAPPER_H_
+#define COMPONENTS_IMAGE_FETCHER_IOS_IOS_IMAGE_DATA_FETCHER_WRAPPER_H_
+
+#import <Foundation/Foundation.h>
+
+#include "base/memory/ref_counted.h"
+#include "components/data_use_measurement/core/data_use_user_data.h"
+#import "components/image_fetcher/image_data_fetcher.h"

[sdefresne, 2017/02/01 09:43:44]

#import -> #include

[gambard, 2017/02/02 10:03:46]

Done.

+
+namespace base {
+class TaskRunner;
+}
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+class GURL;
+
+namespace image_fetcher {
+
+// Callback that informs of the download of an image encoded in |data|.
+using IOSImageDataFetcherCallback = void (^)(NSData* data);
+
+class IOSImageDataFetcherWrapper {
+ public:
+  using DataUseServiceName = data_use_measurement::DataUseUserData::ServiceName;
+
+  // The TaskRunner is used to decode the image if it is WebP-encoded.
+  IOSImageDataFetcherWrapper(
+      net::URLRequestContextGetter* url_request_context_getter,
+      const scoped_refptr<base::TaskRunner>& task_runner);
+  virtual ~IOSImageDataFetcherWrapper();

[sdefresne, 2017/02/01 09:43:44]

I think you don't need "virtual" here. The class does not have virtual methods
and does not appear to be designed to be inherited from.

[gambard, 2017/02/02 10:03:46]

I am inheriting to create mock for tests (in a future CL).

+
+  // 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.
+  // |callback| cannot be nil.
+  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_;
+  ImageDataFetcher image_data_fetcher_;
+};

[sdefresne, 2017/02/01 09:43:44]

DISALLOW_COPY_AND_ASSIGN(IOSImageDataFetcherWrapper)

[gambard, 2017/02/02 10:03:46]

Done.

+}  // namespace image_fetcher

[sdefresne, 2017/02/01 09:43:44]

nit: blank line before closing the namespace or remove the one after opening it

[gambard, 2017/02/02 10:03:46]

Done.

+
+#endif  // COMPONENTS_IMAGE_FETCHER_IOS_IOS_IMAGE_DATA_FETCHER_WRAPPER_H_