Eliminate BrowserThread usage from PasswordStoreDefault.

chrome/browser/password_manager/password_store.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 CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_H_
 #define CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_H_
 
 #include <vector>
 
 #include "base/callback.h"
@@ skipping 164 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(PasswordStoreTest, IgnoreOldWwwGoogleLogins);
 
   virtual ~PasswordStore();
 
   // Schedules the given |task| to be run on the PasswordStore's TaskRunner.
   bool ScheduleTask(const base::Closure& task);
 
   // Get the TaskRunner to use for PasswordStore background tasks.
   // By default, a SingleThreadTaskRunner on the DB thread is used, but
   // subclasses can override.
-  virtual scoped_refptr<base::SequencedTaskRunner> GetBackgroundTaskRunner();
+  virtual scoped_refptr<base::SingleThreadTaskRunner> GetBackgroundTaskRunner();
 
   // These will be run in PasswordStore's own thread.
   // Synchronous implementation that reports usage metrics.
   virtual void ReportMetricsImpl() = 0;
   // Synchronous implementation to add the given login.
   virtual void AddLoginImpl(const autofill::PasswordForm& form) = 0;
   // Synchronous implementation to update the given login.
   virtual void UpdateLoginImpl(const autofill::PasswordForm& form) = 0;
   // Synchronous implementation to remove the given login.
   virtual void RemoveLoginImpl(const autofill::PasswordForm& form) = 0;
@@ skipping 72 matching lines @@
       PasswordStore::GetLoginsRequest* request,
       const std::vector<autofill::PasswordForm*>& matched_forms);
 
   // The observers.
   ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(PasswordStore);
 };
 
 #endif  // CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_H_