Handle null callbacks in OnFaviconDownloaded

components/ntp_tiles/icon_cacher_impl_unittest.cc

 // 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.
 
 #include "components/ntp_tiles/icon_cacher_impl.h"
 
 #include <set>
 #include <utility>
 
 #include "base/files/scoped_temp_dir.h"
@@ skipping 257 matching lines @@
         .WillOnce(FailFetch());
   }
 
   IconCacherImpl cacher(&favicon_service_, std::move(image_fetcher_));
   cacher.StartFetch(site_, done.Get(), done.Get());
   WaitForTasksToFinish();
   EXPECT_FALSE(IconIsCachedFor(site_.url, favicon_base::FAVICON));
   EXPECT_FALSE(IconIsCachedFor(site_.url, favicon_base::TOUCH_ICON));
 }
 
+TEST_F(IconCacherTest, HandlesEmptyClosuresNicely) {

[Marc Treib, 2017/03/03 10:29:42]

nit: s/Closures/Callbacks/ ?
(The fact that they have no params IMO doesn't really matter here)

[fhorschig, 2017/03/03 10:35:26]

Done.

+  EXPECT_CALL(*image_fetcher_, SetDataUseServiceName(_));
+  EXPECT_CALL(*image_fetcher_, SetDesiredImageFrameSize(_));
+  ON_CALL(*image_fetcher_, StartOrQueueNetworkRequest(_, _, _))
+      .WillByDefault(PassFetch(128, 128));
+  IconCacherImpl cacher(&favicon_service_, std::move(image_fetcher_));
+  cacher.StartFetch(site_, base::Closure(), base::Closure());
+  WaitForTasksToFinish();
+}
+
 TEST_F(IconCacherTest, ProvidesDefaultIconAndSucceedsWithFetching) {
   // We are not interested which delegate function actually handles the call to
   // |GetNativeImageNamed| as long as we receive the right image.
   ON_CALL(mock_resource_delegate_, GetNativeImageNamed(12345))
       .WillByDefault(Return(gfx::test::CreateImage(64, 64)));
   ON_CALL(mock_resource_delegate_, GetImageNamed(12345))
       .WillByDefault(Return(gfx::test::CreateImage(64, 64)));
   base::MockCallback<base::Closure> preliminary_icon_available;
   base::MockCallback<base::Closure> icon_available;
   base::RunLoop default_loop;
@@ skipping 22 matching lines @@
               Eq(gfx::Size(64, 64)));  // Compares dimensions, not objects.
 
   // Let the fetcher continue and wait for the second call of the callback.
   fetch_loop.Run();  // Wait for the updated image.
   EXPECT_THAT(GetCachedIconFor(site_.url, favicon_base::TOUCH_ICON).Size(),
               Eq(gfx::Size(128, 128)));  // Compares dimensions, not objects.
 }
 
 }  // namespace
 }  // namespace ntp_tiles