Provide lazy CommitPendingWrites in addition to eager SavePersistentPrefs.

chrome/common/persistent_pref_store.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_COMMON_PERSISTENT_PREF_STORE_H_
 #define CHROME_COMMON_PERSISTENT_PREF_STORE_H_
 #pragma once
 
 #include <string>
 
 #include <chrome/common/pref_store.h>
 
+class NotificationSource;
+
 // This interface is complementary to the PrefStore interface, declaring
 // additional functionality that adds support for setting values and persisting
 // the data to some backing store.
 class PersistentPrefStore : public PrefStore {
  public:
   virtual ~PersistentPrefStore() {}
 
   // Unique integer code for each type of error so we can report them
   // distinctly in a histogram.
   // NOTE: Don't change the order here as it will change the server's meaning
@@ skipping 37 matching lines @@
   virtual bool ReadOnly() const = 0;
 
   // Reads the preferences from disk.
   virtual PrefReadError ReadPrefs() = 0;
 
   // Writes the preferences to disk immediately.
   virtual bool WritePrefs() = 0;
 
   // Schedules an asynchronous write operation.
   virtual void ScheduleWritePrefs() = 0;
+
+  // Lands any pending writes to disk.
+  virtual void CommitPendingWrite() = 0;
+
+  // Sets source to use for PREF_COMMITTED notification.
+  virtual void SetNotificationSource(const NotificationSource& source) = 0;
 };
 
 #endif  // CHROME_COMMON_PERSISTENT_PREF_STORE_H_