Create an AutofillBackend interface

components/autofill/browser/webdata/autofill_webdata_service.h

 // Copyright (c) 2012 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_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_WEBDATA_SERVICE_H_
 #define COMPONENTS_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_WEBDATA_SERVICE_H_
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/supports_user_data.h"
 #include "components/autofill/browser/webdata/autofill_webdata.h"
 #include "components/autofill/common/form_field_data.h"
 #include "components/webdata/common/web_data_results.h"
 #include "components/webdata/common/web_data_service_base.h"
 #include "components/webdata/common/web_data_service_consumer.h"
 #include "components/webdata/common/web_database.h"
 
 class WebDatabaseService;
 
 namespace content {
 class BrowserContext;
 }
 
 namespace autofill {
 
 class AutofillChange;
 class AutofillProfile;
 class AutofillWebDataBackend;
 class AutofillWebDataServiceObserverOnDBThread;
 class AutofillWebDataServiceObserverOnUIThread;
 class CreditCard;
+class SyncableServiceDelegate;
 
 // API for Autofill web data.
 class AutofillWebDataService : public AutofillWebData,
                                public WebDataServiceBase {
  public:
+  typedef base::Callback<void(base::WeakPtr<SyncableServiceDelegate>)>
+      DelegateOnDBCallback;
+
   AutofillWebDataService();
 
   AutofillWebDataService(scoped_refptr<WebDatabaseService> wdbs,
                          const ProfileErrorCallback& callback);
 
   // Retrieve an AutofillWebDataService for the given context.
   // Can return NULL in some contexts.
   static scoped_refptr<AutofillWebDataService> FromBrowserContext(
       content::BrowserContext* context);
 
@@ skipping 40 matching lines @@
 
   void AddObserver(AutofillWebDataServiceObserverOnUIThread* observer);
   void RemoveObserver(AutofillWebDataServiceObserverOnUIThread* observer);
 
   // Returns a SupportsUserData objects that may be used to store data
   // owned by the DB thread on this object. Should be called only from
   // the DB thread, and will be destroyed on the DB thread soon after
   // |ShutdownOnUIThread()| is called.
   base::SupportsUserData* GetDBUserData();
 
+  // Asynchronously gets an instance of |AutofillBackendDelegate|, which can be
+  // used to do work on the DB thread. This method is meant to be called from
+  // the UI thread, but the callback will be called on the DB thread.
+  // The delegate instance is owned by |AutofillWebDataBackend|, and so has the
+  // same lifetime as |AutofillWebDataService|.
+  void GetDelegateOnDB(const DelegateOnDBCallback& del_callback);

[Ilya Sherman, 2013/05/07 00:02:43]

nit: Please don't use abbreviations like "del" in names.

+
  protected:
   virtual ~AutofillWebDataService();
 
   virtual void ShutdownOnDBThread();
 
+  // All vended weak pointers are invalidated in ShutdownDatabase().

[Jói, 2013/05/06 23:08:39]

Suggest documenting which thread this factory is used from, since it can only be
used from one.

[Cait (Slow), 2013/05/07 19:22:07]

Done.

+  base::WeakPtrFactory<AutofillWebDataService> weak_ptr_factory_;
+
  private:
   // This makes the destructor public, and thus allows us to aggregate
   // SupportsUserData. It is private by default to prevent incorrect
   // usage in class hierarchies where it is inherited by
   // reference-counted objects.
   class SupportsUserDataAggregatable : public base::SupportsUserData {
    public:
     SupportsUserDataAggregatable() {}
     virtual ~SupportsUserDataAggregatable() {}
    private:
@@ skipping 10 matching lines @@
   ObserverList<AutofillWebDataServiceObserverOnUIThread> ui_observer_list_;
 
   scoped_refptr<AutofillWebDataBackend> autofill_backend_;
 
   DISALLOW_COPY_AND_ASSIGN(AutofillWebDataService);
 };
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_WEBDATA_SERVICE_H_