Add foundation for trimming the AffiliationDatabase.

components/password_manager/core/browser/affiliation_service.h

Index: components/password_manager/core/browser/affiliation_service.h
diff --git a/components/password_manager/core/browser/affiliation_service.h b/components/password_manager/core/browser/affiliation_service.h
index adc2349eae2692c9f9f4c8f336c284dc8f578d07..fd81a3bd5ca54a5c8775339c708e52f4114bbfd4 100644
--- a/components/password_manager/core/browser/affiliation_service.h
+++ b/components/password_manager/core/browser/affiliation_service.h
@@ -142,6 +142,12 @@ class AffiliationService : public KeyedService {
   // 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