Use component ImageFetcher instead of iOS one.

ios/chrome/browser/suggestions/BUILD.gn

 # Copyright 2016 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.
 
 source_set("suggestions") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
-    "image_fetcher_impl.h",
-    "image_fetcher_impl.mm",
     "ios_image_decoder_impl.h",
     "ios_image_decoder_impl.mm",
     "suggestions_service_factory.h",
     "suggestions_service_factory.mm",
   ]
   deps = [
     "//base",
     "//components/browser_sync",
     "//components/image_fetcher",
     "//components/image_fetcher/ios",
@@ skipping 18 matching lines @@
   sources = [
     "ios_image_decoder_impl_unittest.mm",
   ]
   deps = [
     ":suggestions",
     "//base",
     "//testing/gtest",
     "//ui/gfx",
   ]
 }