Extend LargeIconService to fetch missing favicons from a Google server

ios/chrome/browser/ui/history/favicon_view_provider_unittest.mm

 // 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.
 
 #import "ios/chrome/browser/ui/history/favicon_view_provider.h"
 
 #include <memory>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
@@ skipping 62 matching lines @@
   CHECK(result.is_valid());
   return result;
 }
 
 class FaviconViewProviderTest : public PlatformTest {
  protected:
   void SetUp() override {
     DCHECK_CURRENTLY_ON(web::WebThread::UI);
     PlatformTest::SetUp();
     large_icon_service_.reset(new favicon::LargeIconService(
-        &mock_favicon_service_, base::ThreadTaskRunnerHandle::Get()));
+        &mock_favicon_service_, base::ThreadTaskRunnerHandle::Get(),
+        /*image_fetcher=*/nullptr));
 
     EXPECT_CALL(mock_favicon_service_, GetLargestRawFaviconForPageURL(
                                            GURL(kTestFaviconURL), _, _, _, _))
         .WillRepeatedly(PostReply<5>(CreateTestBitmap()));
   }
 
   web::TestWebThreadBundle thread_bundle_;
   testing::StrictMock<favicon::MockFaviconService> mock_favicon_service_;
   std::unique_ptr<favicon::LargeIconService> large_icon_service_;
   base::CancelableTaskTracker cancelable_task_tracker_;
@@ skipping 49 matching lines @@
     EXPECT_NSEQ(defaultText, viewProvider.fallbackText);
     EXPECT_NSEQ(defaultTextColor, viewProvider.fallbackTextColor);
     EXPECT_NSEQ(defaultBackgroundColor, viewProvider.fallbackBackgroundColor);
   };
   [[[mock_delegate stub] andDo:confirmationBlock]
       faviconViewProviderFaviconDidLoad:item];
   EXPECT_OCMOCK_VERIFY(mock_delegate);
 }
 
 }  // namespace