[Offline pages] Resetting offline page metadata store to handle LOAD/INIT failures

components/offline_pages/offline_page_metadata_store_sql.h

Index: components/offline_pages/offline_page_metadata_store_sql.h
diff --git a/components/offline_pages/offline_page_metadata_store_sql.h b/components/offline_pages/offline_page_metadata_store_sql.h
index c26cae8fb3e6653ee5f3224d2cda2cc55115607c..f286b441491d4e8f4dde9b8e559b579d126f006b 100644
--- a/components/offline_pages/offline_page_metadata_store_sql.h
+++ b/components/offline_pages/offline_page_metadata_store_sql.h
@@ -58,6 +58,7 @@ class OfflinePageMetadataStoreSQL : public OfflinePageMetadataStore {
   ~OfflinePageMetadataStoreSQL() override;
 
   // Implementation methods.
+  void Initialize(const InitializeCallback& callback) override;
   void GetOfflinePages(const LoadCallback& callback) override;
   void AddOfflinePage(const OfflinePageItem& offline_page,
                       const AddCallback& callback) override;
@@ -65,24 +66,19 @@ class OfflinePageMetadataStoreSQL : public OfflinePageMetadataStore {
                           const UpdateCallback& callback) override;
   void RemoveOfflinePages(const std::vector<int64_t>& offline_ids,
                           const UpdateCallback& callback) override;
-  void Reset(const ResetCallback& callback) override;
+  void Reset(const InitializeCallback& callback) override;

[jianli, 2016/11/16 01:34:50]

Will this be ResetCallback?

[fgorski, 2016/11/16 19:10:13]

Done.

   StoreState state() const override;
 
   // Helper function used to force incorrect state for testing purposes.
   void SetStateForTesting(StoreState state, bool reset_db);
 
  private:
-  // Used to initialize DB connection.
-  void OpenConnection();
-  void OnOpenConnectionDone(StoreState state);
+  // Used to conclude opening/resetting DB connection.
+  void OnOpenConnectionDone(const InitializeCallback& callback, bool success);
+  void OnResetDone(const ResetCallback& callback, bool success);
 
-  // Used to reset DB connection.
-  void OnResetDone(const ResetCallback& callback, StoreState state);
-
-  // Helper function that checks whether a valid DB connection is present.
-  // Returns true if valid connection is present, otherwise it returns false and
-  // calls the provided callback as a shortcut.
-  bool CheckDb(const base::Closure& callback);
+  // Checks whether a valid DB connection is present and store state is LOADED.
+  bool CheckDb();
 
   // Background thread where all SQL access should be run.
   scoped_refptr<base::SequencedTaskRunner> background_task_runner_;