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..b62b782948a6465bc908a02e78499870d05e4e27
--- /dev/null
+++ b/components/bookmarks/browser/typed_count_sorter.h
@@ -0,0 +1,35 @@
+// 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;
+
+// A sort method for sorting a set of bookmarks in decreasing order according to
+// the number of times each bookmark's URL was typed into the omnibox. Duplicate
+// matches are removed.
+class TypedCountSorter : public TitledUrlNodeSorter {
+ public:
+  explicit TypedCountSorter(BookmarkClient* client);
+  ~TypedCountSorter() override;
+
+  // TitledUrlNodeSorter
+  void SortMatches(const TitledUrlNodeSet& matches,
+                   TitledUrlNodes* sorted_nodes) const override;
+
+ private:
+  BookmarkClient* client_;
+
+  DISALLOW_COPY_AND_ASSIGN(TypedCountSorter);
+};
+
+}
+
+#endif  // COMPONENTS_BOOKMARKS_BROWSER_TYPED_COUNT_SORTER_H_