[NTP::Push] Adding BreakingNewsSuggestionsProvider

components/ntp_snippets/breaking_news/breaking_news_suggestions_provider.h

+// Copyright 2017 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_NTP_SNIPPETS_BREAKING_NEWS_BREAKING_NEWS_SUGGESTIONS_PROVIDER_H_
+#define COMPONENTS_NTP_SNIPPETS_BREAKING_NEWS_BREAKING_NEWS_SUGGESTIONS_PROVIDER_H_
+
+#include "components/ntp_snippets/category.h"
+#include "components/ntp_snippets/content_suggestions_provider.h"
+#include "components/prefs/pref_registry_simple.h"
+
+namespace ntp_snippets {
+class ContentSuggestionsGCMAppHandler;
+}
+
+namespace ntp_snippets {
+
+// Receives breaking news suggestions via GCM push messages, stores them and
+// provides them as content suggestions.
+class BreakingNewsSuggestionsProvider : public ContentSuggestionsProvider {
+ public:
+  BreakingNewsSuggestionsProvider(
+      ContentSuggestionsProvider::Observer* observer,
+      std::unique_ptr<ContentSuggestionsGCMAppHandler> gcm_app_handler);
+  ~BreakingNewsSuggestionsProvider() override;
+
+  // Starts the underlying GCM handler and registers the callback when GCM
+  // receives a message.
+  void Start();
+
+ private:
+  // ContentSuggestionsProvider implementation.
+  CategoryStatus GetCategoryStatus(Category category) override;
+  CategoryInfo GetCategoryInfo(Category category) override;
+  void DismissSuggestion(const ContentSuggestion::ID& suggestion_id) override;
+  void FetchSuggestionImage(const ContentSuggestion::ID& suggestion_id,
+                            const ImageFetchedCallback& callback) override;
+  void Fetch(const Category& category,
+             const std::set<std::string>& known_suggestion_ids,
+             const FetchDoneCallback& callback) override;
+  void ClearHistory(
+      base::Time begin,
+      base::Time end,
+      const base::Callback<bool(const GURL& url)>& filter) override;
+  void ClearCachedSuggestions(Category category) override;
+  void GetDismissedSuggestionsForDebugging(
+      Category category,
+      const DismissedSuggestionsCallback& callback) override;
+  void ClearDismissedSuggestionsForDebugging(Category category) override;
+
+  // Callback called from the GCM handler when new content has been pushed from
+  // the server.
+  void OnNewContentSuggestion(const base::Value& content);
+
+  std::unique_ptr<ContentSuggestionsGCMAppHandler> gcm_app_handler_;
+  const Category provided_category_;
+  CategoryStatus category_status_;
+
+  DISALLOW_COPY_AND_ASSIGN(BreakingNewsSuggestionsProvider);
+};
+
+}  // namespace ntp_snippets
+
+#endif  // COMPONENTS_NTP_SNIPPETS_BREAKING_NEWS_BREAKING_NEWS_SUGGESTIONS_PROVIDER_H_