[Sync] Restore previous session if no tabbed windows present

components/sync_sessions/sessions_sync_manager.h

 // Copyright 2014 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_SYNC_SESSIONS_SESSIONS_SYNC_MANAGER_H_
 #define COMPONENTS_SYNC_SESSIONS_SESSIONS_SYNC_MANAGER_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 101 matching lines @@
   FaviconCache* GetFaviconCache();
 
   // Triggers garbage collection of stale sessions (as defined by
   // |stale_session_threshold_days_|). This is called every time we see new
   // sessions data downloaded (sync cycles complete).
   void DoGarbageCollection();
 
  private:
   friend class extensions::ExtensionSessionsTest;
   friend class SessionsSyncManagerTest;
-  FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest, PopulateSessionHeader);
+  FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest, PopulateSyncedSession);
   FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest, PopulateSessionWindow);
   FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest, ValidTabs);
   FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest, SetSessionTabFromDelegate);
   FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest,
                            SetSessionTabFromDelegateNavigationIndex);
   FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest,
                            SetSessionTabFromDelegateCurrentInvalid);
   FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest, BlockedNavigations);
   FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest, DeleteForeignSession);
   FRIEND_TEST_ALL_PREFIXES(SessionsSyncManagerTest,
@@ skipping 47 matching lines @@
 
   // Delete a foreign session and all its sync data.
   // |change_output| *must* be provided as a link to the SyncChange pipeline
   // that exists in the caller's context. This function will append necessary
   // changes for processing later.
   void DeleteForeignSessionInternal(const std::string& tag,
                                     syncer::SyncChangeList* change_output);
 
   // Used to populate a session header from the session specifics header
   // provided.
-  static void PopulateSessionHeaderFromSpecifics(
+  void PopulateSyncedSessionFromSpecifics(
+      const std::string& session_tag,
       const sync_pb::SessionHeader& header_specifics,
       base::Time mtime,
-      SyncedSession* session_header);
+      SyncedSession* synced_session);
 
-  // Builds |session_window| from the session specifics window
+  // Builds |synced_session_window| from the session specifics window
   // provided and updates the SessionTracker with foreign session data created.
-  void BuildSyncedSessionFromSpecifics(
+  void PopulateSyncedSessionWindowFromSpecifics(
       const std::string& session_tag,
       const sync_pb::SessionWindow& specifics,
       base::Time mtime,
       SyncedSessionWindow* synced_session_window);
 
   // Resync local window information. Updates the local sessions header node
   // with the status of open windows and the order of tabs they contain. Should
   // only be called for changes that affect a window, not a change within a
   // single tab.
   //
@@ skipping 31 matching lines @@
   // case we can't do a full association, but we still want to update tab IDs
   // as they may have changed after a session was restored.  This method
   // compares new_tab_id and new_window_id against the previously persisted tab
   // ID and window ID (from our TabNodePool) and updates them if either differs.
   void AssociateRestoredPlaceholderTab(
       const SyncedTabDelegate& tab_delegate,
       SessionID::id_type new_tab_id,
       SessionID::id_type new_window_id,
       syncer::SyncChangeList* change_output);
 
+  // Updates a sync tab node based on local tab information.

[skym, 2017/04/17 20:37:02]

I don't like the term update being used here. Yes, you're using an
ACTION_UPDATE, but this is really preparing the sync change to be given to sync
for an existing tab. What do you think of AppendChangeForExistingTab().

[Nicolas Zea, 2017/04/17 21:24:54]

Done.

+  void UpdateTabSpecifics(int sync_id,
+                          const sessions::SessionTab& tab,
+                          syncer::SyncChangeList* change_output);
+
   // Stops and re-starts syncing to rebuild association mappings. Returns true
   // when re-starting succeeds.
   // See |local_tab_pool_out_of_sync_|.
   bool RebuildAssociations();
 
   // Validates the content of a SessionHeader protobuf.
   // Returns false if validation fails.
   static bool IsValidSessionHeader(const sync_pb::SessionHeader& header);
 
   // Calculates the tag hash from a specifics object. Calculating the hash is
@@ skipping 59 matching lines @@
 
   // Callback to inform sync that a sync data refresh is requested.
   base::Closure datatype_refresh_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionsSyncManager);
 };
 
 }  // namespace sync_sessions
 
 #endif  // COMPONENTS_SYNC_SESSIONS_SESSIONS_SYNC_MANAGER_H_