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

components/ntp_snippets/category_factory.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_snippets/category_factory.h"
-
-#include <algorithm>
-
-#include "base/logging.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/stringprintf.h"
-
-namespace ntp_snippets {
-
-CategoryFactory::CategoryFactory() {
-  // Add all local categories in a fixed order.
-  AddKnownCategory(KnownCategories::DOWNLOADS);
-  AddKnownCategory(KnownCategories::RECENT_TABS);
-  AddKnownCategory(KnownCategories::FOREIGN_TABS);
-  AddKnownCategory(KnownCategories::BOOKMARKS);
-  AddKnownCategory(KnownCategories::PHYSICAL_WEB_PAGES);
-
-  DCHECK_EQ(static_cast<size_t>(KnownCategories::LOCAL_CATEGORIES_COUNT),
-            ordered_categories_.size());
-
-  // Known remote categories come after. Other remote categories will be ordered
-  // after these depending on when providers notify us about a related change.
-  AddKnownCategory(KnownCategories::ARTICLES);
-}
-
-CategoryFactory::~CategoryFactory() = default;
-
-Category CategoryFactory::FromKnownCategory(KnownCategories known_category) {
-  if (known_category < KnownCategories::LOCAL_CATEGORIES_COUNT) {
-    // Local categories should have been added already.
-    DCHECK(CategoryExists(static_cast<int>(known_category)));
-  } else {
-    DCHECK_GT(known_category, KnownCategories::REMOTE_CATEGORIES_OFFSET);
-  }
-  return InternalFromID(static_cast<int>(known_category));
-}
-
-Category CategoryFactory::FromRemoteCategory(int remote_category) {
-  DCHECK_GT(remote_category, 0);
-  return InternalFromID(
-      static_cast<int>(KnownCategories::REMOTE_CATEGORIES_OFFSET) +
-      remote_category);
-}
-
-Category CategoryFactory::FromIDValue(int id) {
-  DCHECK_GE(id, 0);
-  DCHECK(id < static_cast<int>(KnownCategories::LOCAL_CATEGORIES_COUNT) ||
-         id > static_cast<int>(KnownCategories::REMOTE_CATEGORIES_OFFSET));
-  return InternalFromID(id);
-}
-
-bool CategoryFactory::CompareCategories(const Category& left,
-                                        const Category& right) const {
-  if (left == right) {
-    return false;
-  }
-  return std::find(ordered_categories_.begin(), ordered_categories_.end(),
-                   left) < std::find(ordered_categories_.begin(),
-                                     ordered_categories_.end(), right);
-}
-
-////////////////////////////////////////////////////////////////////////////////
-// Private methods
-
-bool CategoryFactory::CategoryExists(int id) {
-  return std::find(ordered_categories_.begin(), ordered_categories_.end(),
-                   Category(id)) != ordered_categories_.end();
-}
-
-void CategoryFactory::AddKnownCategory(KnownCategories known_category) {
-  InternalFromID(static_cast<int>(known_category));
-}
-
-Category CategoryFactory::InternalFromID(int id) {
-  auto it = std::find(ordered_categories_.begin(), ordered_categories_.end(),
-                      Category(id));
-  if (it != ordered_categories_.end()) {
-    return *it;
-  }
-
-  Category category(id);
-  ordered_categories_.push_back(category);
-  return category;
-}
-
-}  // namespace ntp_snippets