[Sync] Ensure we don't hold a transaction when we access password store.

chrome/browser/sync/glue/password_change_processor.h

 // Copyright (c) 2011 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_SYNC_GLUE_PASSWORD_CHANGE_PROCESSOR_H_
 #define CHROME_BROWSER_SYNC_GLUE_PASSWORD_CHANGE_PROCESSOR_H_
 #pragma once
 
 #include "chrome/browser/sync/glue/change_processor.h"
 
 #include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "chrome/browser/sync/glue/password_model_associator.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
 #include "content/common/notification_type.h"
 
 class PasswordStore;
 class MessageLoop;
 class NotificationService;
 
 namespace browser_sync {
 
-class PasswordModelAssociator;
 class UnrecoverableErrorHandler;
 
 // This class is responsible for taking changes from the password backend and
 // applying them to the sync_api 'syncable' model, and vice versa. All
 // operations and use of this class are from the DB thread on Windows and Linux,
 // or the password thread on Mac.
 class PasswordChangeProcessor : public ChangeProcessor,
                                 public NotificationObserver {
  public:
   PasswordChangeProcessor(PasswordModelAssociator* model_associator,
                           PasswordStore* password_store,
                           UnrecoverableErrorHandler* error_handler);
   virtual ~PasswordChangeProcessor();
 
   // NotificationObserver implementation.
   // Passwords -> sync_api model change application.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
-                       const NotificationDetails& details);
+                       const NotificationDetails& details) OVERRIDE;
 
   // sync_api model -> WebDataService change application.
   virtual void ApplyChangesFromSyncModel(
       const sync_api::BaseTransaction* trans,
       const sync_api::SyncManager::ChangeRecord* changes,
-      int change_count);
+      int change_count) OVERRIDE;
+
+  // Commit changes buffered during ApplyChanges. We must commit them to the
+  // password store only after the sync_api transaction is released, else there
+  // is risk of deadlock due to the password store posting tasks to the UI
+  // thread (http://crbug.com/70658).
+  virtual void CommitChangesFromSyncModel() OVERRIDE;
 
  protected:
-  virtual void StartImpl(Profile* profile);
-  virtual void StopImpl();
+  virtual void StartImpl(Profile* profile) OVERRIDE;
+  virtual void StopImpl() OVERRIDE;
 
  private:
   void StartObserving();
   void StopObserving();
 
   // The two models should be associated according to this ModelAssociator.
   PasswordModelAssociator* model_associator_;
 
   // The model we are processing changes from.  This is owned by the
   // WebDataService which is kept alive by our data type controller
   // holding a reference.
   PasswordStore* password_store_;
 
+  // Buffers used between ApplyChangesFromSyncModel and
+  // CommitChangesFromSyncModel.
+  PasswordModelAssociator::PasswordVector new_passwords_;
+  PasswordModelAssociator::PasswordVector updated_passwords_;
+  PasswordModelAssociator::PasswordVector deleted_passwords_;
+
   NotificationRegistrar notification_registrar_;
 
   bool observing_;
 
   MessageLoop* expected_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(PasswordChangeProcessor);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_PASSWORD_CHANGE_PROCESSOR_H_