Factor out bookmark-specific sorting logic from BookmarkIndex

components/bookmarks/browser/typed_count_sorter.h

Index: components/bookmarks/browser/typed_count_sorter.h
diff --git a/components/bookmarks/browser/typed_count_sorter.h b/components/bookmarks/browser/typed_count_sorter.h
new file mode 100644
index 0000000000000000000000000000000000000000..eabe0091bf3dd694fb499a4634ae0982c1c04fd9
--- /dev/null
+++ b/components/bookmarks/browser/typed_count_sorter.h
@@ -0,0 +1,34 @@
+// 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.
+
+#ifndef COMPONENTS_BOOKMARKS_BROWSER_TYPED_COUNT_SORTER_H_
+#define COMPONENTS_BOOKMARKS_BROWSER_TYPED_COUNT_SORTER_H_
+
+#include "base/macros.h"
+#include "components/bookmarks/browser/titled_url_node_sorter.h"
+
+namespace bookmarks {
+
+class BookmarkClient;
+
+class TypedCountSorter : public TitledUrlNodeSorter {
+ public:
+  TypedCountSorter(BookmarkClient* client);

[sky, 2016/12/12 20:46:10]

explicit

[mattreynolds, 2016/12/12 22:09:14]

Done.

+  ~TypedCountSorter();

[sky, 2016/12/12 20:46:10]

override

[mattreynolds, 2016/12/12 22:09:14]

Done.

+
+  // Constructs |sorted_nodes| by taking the matches in |matches| and sorting
+  // them in decreasing order of typed count (if supported by the client) and
+  // deduping them.
+  void SortMatches(const TitledUrlNodeSet& matches,

[sky, 2016/12/12 20:46:10]

Chrome style is to not document this and instead prefix with the class you are
overriding from. See chromium style guide for more details. I would place the
description you have here as a class description (with a bit of cleanup).

[mattreynolds, 2016/12/12 22:09:14]

Done.

+                   TitledUrlNodes* sorted_nodes) const override;
+
+ private:
+  BookmarkClient* client_;
+
+  DISALLOW_COPY_AND_ASSIGN(TypedCountSorter);
+};
+
+}
+
+#endif  // COMPONENTS_BOOKMARKS_BROWSER_TYPED_COUNT_SORTER_H_