Use 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"
@@ skipping 23 matching lines @@
   IOSImageDataFetcherWrapper(
       net::URLRequestContextGetter* url_request_context_getter,
       const scoped_refptr<base::TaskRunner>& task_runner);
   virtual ~IOSImageDataFetcherWrapper();
 
   // 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);
+  virtual 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_;
 
   DISALLOW_COPY_AND_ASSIGN(IOSImageDataFetcherWrapper);
 };
 
 }  // namespace image_fetcher
 
 #endif  // COMPONENTS_IMAGE_FETCHER_IOS_IOS_IMAGE_DATA_FETCHER_WRAPPER_H_