Add foundation for trimming the AffiliationDatabase.

components/password_manager/core/browser/affiliation_service.h

 // Copyright 2015 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_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_SERVICE_H_
 #define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_SERVICE_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 124 matching lines @@
   // same |facet_uri| and with the same |keep_fresh_until|.
   virtual void CancelPrefetch(const FacetURI& facet_uri,
                               const base::Time& keep_fresh_until);
 
   // Wipes results of on-demand fetches and expired prefetches from the cache,
   // but retains information corresponding to facets that are being kept fresh.
   // As no required data is deleted, there will be no network requests directly
   // triggered by this call.
   void TrimCache();
 
+  // Posts a task to the |backend_task_runner| to delete the cache database file
+  // at |db_path|, and all auxiliary files. The database must be closed before

[vasilii, 2015/04/23 13:16:35]

So where is it ensured that the database is closed?

+  // calling this.
+  static void DeleteCache(const base::FilePath& db_path,
+                          base::SingleThreadTaskRunner* backend_task_runner);
+
  private:
   // The backend, owned by this AffiliationService instance, but living on the
   // DB thread. It will be deleted asynchronously during shutdown on the DB
   // thread, so it will outlive |this| along with all its in-flight tasks.
   AffiliationBackend* backend_;
 
   // TaskRunner to be used to run the |backend_| (usually the DB thread).
   scoped_refptr<base::SingleThreadTaskRunner> backend_task_runner_;
 
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<AffiliationService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AffiliationService);
 };
 
 }  // namespace password_manager
 
 #endif  // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_SERVICE_H_