Use Observer to notify of WebDB load instead of callbacks

components/webdata/common/web_database_service.h

 // Copyright 2013 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.
 
 // Chromium settings and storage represent user-selected preferences and
 // information and MUST not be extracted, overwritten or modified except
 // through Chromium defined APIs.
 
 #ifndef COMPONENTS_WEBDATA_COMMON_WEB_DATABASE_SERVICE_H_
 #define COMPONENTS_WEBDATA_COMMON_WEB_DATABASE_SERVICE_H_
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "components/webdata/common/web_data_service_base.h"
 #include "components/webdata/common/web_database.h"
 #include "components/webdata/common/webdata_export.h"
 
 class WebDataServiceBackend;
 class WebDataRequestManager;
 
 namespace content {
 class BrowserContext;
 }
@@ skipping 14 matching lines @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
 class WEBDATA_EXPORT WebDatabaseService
     : public base::RefCountedThreadSafe<
           WebDatabaseService,
           content::BrowserThread::DeleteOnUIThread> {
  public:
   typedef base::Callback<scoped_ptr<WDTypedResult>(WebDatabase*)> ReadTask;
   typedef base::Callback<WebDatabase::State(WebDatabase*)> WriteTask;
-  typedef base::Callback<void(sql::InitStatus)> InitCallback;
 
   // Takes the path to the WebDatabase file.
   explicit WebDatabaseService(const base::FilePath& path);
 
   // Adds |table| as a WebDatabaseTable that will participate in
   // managing the database, transferring ownership. All calls to this
   // method must be made before |LoadDatabase| is called.
   virtual void AddTable(scoped_ptr<WebDatabaseTable> table);
 
   // Initializes the web database service. Takes a callback which will return
   // the status of the DB after the init.
-  virtual void LoadDatabase(const InitCallback& callback);
+  virtual void LoadDatabase();
 
   // Unloads the database without actually shutting down the service.  This can
   // be used to temporarily reduce the browser process' memory footprint.
   virtual void UnloadDatabase();
 
   // Unloads database and will not reload.
   virtual void ShutdownDatabase();
 
   // Gets a ptr to the WebDatabase (owned by WebDatabaseService).
   // TODO(caitkp): remove this method once SyncServices no longer depend on it.
   virtual WebDatabase* GetDatabaseOnDB() const;
 
   // Schedule an update/write task on the DB thread.
   virtual void ScheduleDBTask(
       const tracked_objects::Location& from_here,
       const WriteTask& task);
 
   // Schedule a read task on the DB thread.
   virtual WebDataServiceBase::Handle ScheduleDBTaskWithResult(
       const tracked_objects::Location& from_here,
       const ReadTask& task,
       WebDataServiceConsumer* consumer);
 
   // Cancel an existing request for a task on the DB thread.
   // TODO(caitkp): Think about moving the definition of the Handle type to
   // somewhere else.
   virtual void CancelRequest(WebDataServiceBase::Handle h);
 
+  void AddObserver(WebDatabaseObserver* observer);
+  void RemoveObserver(WebDatabaseObserver* observer);
+
  private:
+  class BackendDelegate;
   friend struct content::BrowserThread::DeleteOnThread<
       content::BrowserThread::UI>;
   friend class base::DeleteHelper<WebDatabaseService>;
   // We have to friend RCTS<> so WIN shared-lib build is happy (crbug/112250).
   friend class base::RefCountedThreadSafe<WebDatabaseService,
       content::BrowserThread::DeleteOnUIThread>;
+  friend class BackendDelegate;
 
   virtual ~WebDatabaseService();
 
+  void OnDatabaseLoadDone(sql::InitStatus status);
+
   base::FilePath path_;
 
   // The primary owner is |WebDatabaseService| but is refcounted because
   // PostTask on DB thread may outlive us.
   scoped_refptr<WebDataServiceBackend> wds_backend_;
+
+  ObserverList<WebDatabaseObserver> observer_list_;
+
+  // All vended weak pointers are invalidated in Cleanup().

[Jói, 2013/04/17 10:52:04]

Cleanup -> ShutdownDatabase

[Cait (Slow), 2013/04/18 15:07:48]

Done.

+  base::WeakPtrFactory<WebDatabaseService> weak_ptr_factory_;
 };
 
 #endif  // COMPONENTS_WEBDATA_COMMON_WEB_DATABASE_SERVICE_H_