[Offline Pages] Set up the initial prefetching service.

chrome/browser/android/offline_pages/offline_page_suggestions_observer.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 CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_SUGGESTIONS_OBSERVER_H_
+#define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_SUGGESTIONS_OBSERVER_H_
+
+#include <memory>
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "components/ntp_snippets/content_suggestions_service.h"
+#include "components/offline_pages/core/offline_page_types.h"
+
+namespace content {
+class BrowserContext;
+}  // namespace content
+
+namespace ntp_snippets {
+class Category;
+}
+
+namespace offline_pages {
+
+class OfflinePageModel;
+
+class OfflinePageSuggestionsObserver

[Dmitry Titov, 2017/04/11 01:17:13]

Perhaps this can be just SuggestionObserver.

[carlosk, 2017/04/11 17:31:36]

Please add class comment.

[dewittj, 2017/04/11 21:25:48]

Done.

[dewittj, 2017/04/11 21:25:48]

Done.

+    : public ntp_snippets::ContentSuggestionsService::Observer,
+      base::SupportsUserData::Data {
+ public:
+  // Abstract delegate for easy testing.
+  class Delegate {
+   public:
+    virtual std::vector<GURL> GetSuggestionURLs() = 0;
+    virtual void GetPagesWithURLs(
+        const std::vector<GURL>& suggestion_urls,
+        const MultipleOfflinePageItemCallback& callback) = 0;
+    virtual ~Delegate() = default;
+  };
+
+  // This API creates a new OfflinePageSuggestionsObserver and adds it as an
+  // observer to the ContentSuggestionsService provided.  Its lifetime is
+  // self-managed, and it deletes itself upon receiving the
+  // |ContentSuggestionsServiceShutdown| signal using an asynchronous
+  // |DeleteSoon|.
+  static void ObserveContentSuggestionsService(
+      content::BrowserContext* browser_context,
+      offline_pages::OfflinePageModel* offline_page_model,
+      ntp_snippets::ContentSuggestionsService* service);
+  OfflinePageSuggestionsObserver(content::BrowserContext* browser_context,

[Dmitry Titov, 2017/04/11 01:17:13]

nice to add an empty line before ctor.

[dewittj, 2017/04/11 21:25:48]

Done.

+                                 std::unique_ptr<Delegate> delegate,
+                                 const ntp_snippets::Category& category);
+  ~OfflinePageSuggestionsObserver() override;
+
+  // ContentSuggestionsService::Observer overrides
+  void OnNewSuggestions(ntp_snippets::Category category) override;
+  void OnCategoryStatusChanged(
+      ntp_snippets::Category category,
+      ntp_snippets::CategoryStatus new_status) override;
+  void OnSuggestionInvalidated(
+      const ntp_snippets::ContentSuggestion::ID& suggestion_id) override;
+  void OnFullRefreshRequired() override;
+  void ContentSuggestionsServiceShutdown() override;
+
+ private:
+  void GotPagesMatchingSuggestions(const std::vector<GURL>& urls,
+                                   const MultipleOfflinePageItemResult& pages);
+
+  std::unique_ptr<Delegate> delegate_;
+  content::BrowserContext* browser_context_;
+  ntp_snippets::CategoryStatus category_status_ =
+      ntp_snippets::CategoryStatus::INITIALIZING;
+  ntp_snippets::Category category_;
+
+  // This must be the last member for happy destruction order.
+  base::WeakPtrFactory<OfflinePageSuggestionsObserver> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(OfflinePageSuggestionsObserver);
+};
+
+}  // namespace offline_pages
+
+#endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_SUGGESTIONS_OBSERVER_H_