Use IOSImageDataFetcherWrapper for favicon

ios/web/web_state/web_state_impl.h

 // Copyright 2013 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_WEB_WEB_STATE_WEB_STATE_IMPL_H_
 #define IOS_WEB_WEB_STATE_WEB_STATE_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 210 matching lines @@
   GURL GetCurrentURL(URLVerificationTrustLevel* trust_level) const override;
   void ShowTransientContentView(CRWContentView* content_view) override;
   bool IsShowingWebInterstitial() const override;
   WebInterstitial* GetWebInterstitial() const override;
   void OnPasswordInputShownOnHttp() override;
   void OnCreditCardInputShownOnHttp() override;
   void AddScriptCommandCallback(const ScriptCommandCallback& callback,
                                 const std::string& command_prefix) override;
   void RemoveScriptCommandCallback(const std::string& command_prefix) override;
   id<CRWWebViewProxy> GetWebViewProxy() const override;
-  int DownloadImage(const GURL& url,
-                    bool is_favicon,
-                    uint32_t max_bitmap_size,
-                    bool bypass_cache,
-                    const ImageDownloadCallback& callback) override;
   service_manager::InterfaceRegistry* GetMojoInterfaceRegistry() override;
   base::WeakPtr<WebState> AsWeakPtr() override;
 
   // Adds |interstitial|'s view to the web controller's content view.
   void ShowWebInterstitial(WebInterstitialImpl* interstitial);
 
   // Called to dismiss the currently-displayed transient content view.
   void ClearTransientContentView();
 
   // Notifies the delegate that the load progress was updated.
@@ skipping 108 matching lines @@
 
   // Image Fetcher used to images.
   std::unique_ptr<ImageDataFetcher> image_fetcher_;
 
   DISALLOW_COPY_AND_ASSIGN(WebStateImpl);
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_WEB_STATE_WEB_STATE_IMPL_H_