Minor improvements to RecentTabHelper.

chrome/browser/android/offline_pages/recent_tab_helper.h

 // 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 CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 53 matching lines @@
   // 4. If capture is successful, this tab helper removes the suspended request.
   //    Otherwise (navigation to other page, close tab) tab helper un-suspends
   //    the request so the Background Offliner starts working on it.
   // 5. If Chrome is killed at any point, next time Background Offliner loads
   //    it converts all suspended requests from last session into active.
   void ObserveAndDownloadCurrentPage(const ClientId& client_id,
                                      int64_t request_id);
 
  private:
   // Keeps client_id/request_id that will be used for the offline snapshot.
-  struct DownloadPageInfo {
+  struct SnapshotProgressInfo {
    public:
-    DownloadPageInfo(const ClientId& client_id,
-                     int64_t request_id)
-        : client_id_(client_id),
-          request_id_(request_id),
-          page_snapshot_completed_(false) {}
+    // For a downloads snapshot request, where the |request_id| is defined.
+    SnapshotProgressInfo(const ClientId& client_id, int64_t request_id)
+        : client_id(client_id), request_id(request_id) {}
+
+    // For a last_n snapshot request.
+    explicit SnapshotProgressInfo(const ClientId& client_id)
+        : client_id(client_id) {}
+
+    bool IsForLastN();
 
     // The ClientID to go with the offline page.
-    ClientId client_id_;
+    ClientId client_id;
+
     // Id of the suspended request in Background Offliner. Used to un-suspend
     // the request if the capture of the current page was not possible (e.g.
     // the user navigated to another page before current one was loaded).
-    // 0 if this is a "last_1" info.
-    int64_t request_id_;
+    // 0 if this is a "last_n" info.
+    int64_t request_id = OfflinePageModel::kInvalidOfflineId;
+
     // True if there was at least one snapshot successfully completed.
-    bool page_snapshot_completed_;
+    bool page_snapshot_completed = false;
   };
 
   explicit RecentTabHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<RecentTabHelper>;
 
   void EnsureInitialized();
   void ContinueSnapshotWithIdsToPurge(const std::vector<int64_t>& page_ids);
   void ContinueSnapshotAfterPurge(OfflinePageModel::DeletePageResult result);
   void SavePageCallback(OfflinePageModel::SavePageResult result,
                         int64_t offline_id);
   void ReportSnapshotCompleted();
   void ReportDownloadStatusToRequestCoordinator();
   bool IsSamePage() const;
   ClientId GetRecentPagesClientId() const;
 
   // Page model is a service, no ownership. Can be null - for example, in
   // case when tab is in incognito profile.
-  OfflinePageModel* page_model_;
+  OfflinePageModel* page_model_ = nullptr;
 
   // If false, never make snapshots off the attached WebContents.
   // Not page-specific.
-  bool snapshots_enabled_;
+  bool snapshots_enabled_ = false;
 
   // Becomes true during navigation if the page is ready for snapshot as
   // indicated by at least one callback from SnapshotController.
-  bool is_page_ready_for_snapshot_;
+  bool is_page_ready_for_snapshot_ = false;
 
   // Info for the offline page to capture. Null if the tab is not capturing
   // current page.
-  std::unique_ptr<DownloadPageInfo> download_info_;
+  std::unique_ptr<SnapshotProgressInfo> snapshot_info_;
 
   // If empty, the tab does not have AndroidId and can not capture pages.
   std::string tab_id_;
 
   // The URL of the page that is currently being snapshotted. Used to check,
   // during async operations, that WebContents still contains the same page.
   GURL snapshot_url_;
   // This starts out null and used as a flag for EnsureInitialized() to do the
   // initialization only once.
   std::unique_ptr<SnapshotController> snapshot_controller_;
 
   std::unique_ptr<Delegate> delegate_;
 
   base::WeakPtrFactory<RecentTabHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RecentTabHelper);
 };
 
 }  // namespace offline_pages
+
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_