[NTP Snippets] Introduce ContentSuggestion::ID

components/ntp_snippets/content_suggestions_provider.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/content_suggestions_provider.h"
 
 #include "components/ntp_snippets/category_factory.h"
 
 namespace ntp_snippets {
 
 ContentSuggestionsProvider::ContentSuggestionsProvider(
     Observer* observer,
     CategoryFactory* category_factory)
     : observer_(observer), category_factory_(category_factory) {}
 
 ContentSuggestionsProvider::~ContentSuggestionsProvider() = default;
 
-std::string ContentSuggestionsProvider::MakeUniqueID(
-    Category category,
-    const std::string& within_category_id) const {
-  return category_factory()->MakeUniqueID(category, within_category_id);
-}
-
-Category ContentSuggestionsProvider::GetCategoryFromUniqueID(
-    const std::string& unique_id) const {
-  return category_factory()->GetCategoryFromUniqueID(unique_id);
-}
-
-std::string ContentSuggestionsProvider::GetWithinCategoryIDFromUniqueID(
-    const std::string& unique_id) const {
-  return category_factory()->GetWithinCategoryIDFromUniqueID(unique_id);
-}
-
 }  // namespace ntp_snippets