[NTP::SectionOrder] Replace CategoryFactory with a category ranker.

components/ntp_snippets/category_rankers/category_ranker.cc

Index: components/ntp_snippets/category_rankers/category_ranker.cc
diff --git a/components/ntp_snippets/category_rankers/category_ranker.cc b/components/ntp_snippets/category_rankers/category_ranker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..64c14ac314cde3ca99461640419720500647a354
--- /dev/null
+++ b/components/ntp_snippets/category_rankers/category_ranker.cc
@@ -0,0 +1,11 @@
+// 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_snippets/category_rankers/category_ranker.h"
+
+namespace ntp_snippets {
+
+CategoryRanker::~CategoryRanker() = default;

[Marc Treib, 2016/12/15 16:01:18]

I think this could go in the header? (But doesn't really matter I guess)

[vitaliii, 2016/12/15 16:53:50]

Done.

+
+}  // namespace ntp_snippets