Move ImageFetcher to its own target.

ios/chrome/browser/suggestions/image_fetcher_impl.h

 // Copyright 2014 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 IOS_CHROME_BROWSER_SUGGESTIONS_IMAGE_FETCHER_IMPL_H_
 #define IOS_CHROME_BROWSER_SUGGESTIONS_IMAGE_FETCHER_IMPL_H_
 
 #include <memory>
 #include <string>
 
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "components/image_fetcher/image_fetcher.h"
 
 class GURL;
-class ImageFetcher;
 
 namespace base {
 class SequencedWorkerPool;
 }
 
 namespace gfx {
 class Image;
 }
 
 namespace image_fetcher {
 class ImageFetcherDelegate;
+class RawImageFetcher;
 }
 
 namespace net {
 class URLRequestContextGetter;
 }
 
 namespace suggestions {
 
 // A class used to fetch server images asynchronously.
 class ImageFetcherImpl : public image_fetcher::ImageFetcher {
  public:
   ImageFetcherImpl(net::URLRequestContextGetter* url_request_context,
                    base::SequencedWorkerPool* blocking_pool);
   ~ImageFetcherImpl() override;
 
   void SetImageFetcherDelegate(
       image_fetcher::ImageFetcherDelegate* delegate) override;
 
   void SetDataUseServiceName(DataUseServiceName data_use_service_name) override;
 
   void StartOrQueueNetworkRequest(
       const std::string& id,
       const GURL& image_url,
       base::Callback<void(const std::string&, const gfx::Image&)> callback)
       override;
 
  private:
-  std::unique_ptr<::ImageFetcher> imageFetcher_;
+  std::unique_ptr<image_fetcher::RawImageFetcher> imageFetcher_;
 
   image_fetcher::ImageFetcherDelegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageFetcherImpl);
 };
 
 }  // namespace suggestions
 
 #endif  // IOS_CHROME_BROWSER_SUGGESTIONS_IMAGE_FETCHER_IMPL_H_