Move ImageFetcher to its own target.

ios/chrome/browser/net/image_fetcher/mock_image_fetcher.h

 // Copyright 2015 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_NET_MOCK_IMAGE_FETCHER_H_
-#define IOS_CHROME_BROWSER_NET_MOCK_IMAGE_FETCHER_H_
+#ifndef IOS_CHROME_BROWSER_NET_IMAGE_FETCHER_MOCK_IMAGE_FETCHER_H_
+#define IOS_CHROME_BROWSER_NET_IMAGE_FETCHER_MOCK_IMAGE_FETCHER_H_
 
-#import "ios/chrome/browser/net/image_fetcher.h"
+#import "ios/chrome/browser/net/image_fetcher/image_fetcher.h"
 
 #include "testing/gmock/include/gmock/gmock.h"
 
 // Mock the ImageFetcher utility class, which can be used to asynchronously
 // retrieve an image from an URL.
 class MockImageFetcher : public ImageFetcher {
  public:
   explicit MockImageFetcher(const scoped_refptr<base::TaskRunner>& task_runner);
   ~MockImageFetcher() override;
 
   MOCK_METHOD4(StartDownload,
                void(const GURL& url,
                     ImageFetchedCallback callback,
                     const std::string& referrer,
                     net::URLRequest::ReferrerPolicy referrer_policy));
   MOCK_METHOD2(StartDownload,
                void(const GURL& url, ImageFetchedCallback callback));
   MOCK_METHOD1(SetRequestContextGetter,
                void(const scoped_refptr<net::URLRequestContextGetter>&
                         request_context_getter));
 };
 
-#endif  // IOS_CHROME_BROWSER_NET_MOCK_IMAGE_FETCHER_H_
+#endif  // IOS_CHROME_BROWSER_NET_IMAGE_FETCHER_MOCK_IMAGE_FETCHER_H_