Provide lazy CommitPendingWrites in addition to eager SavePersistentPrefs.

chrome/common/important_file_writer.h

Index: chrome/common/important_file_writer.h
diff --git a/chrome/common/important_file_writer.h b/chrome/common/important_file_writer.h
index 34c60674c9504f516fdb3a070eeaa0f8f4c42fe7..72a9c76370550ecb4f8fe0d4eb2cd21de6983ca4 100644
--- a/chrome/common/important_file_writer.h
+++ b/chrome/common/important_file_writer.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -14,6 +14,7 @@
 #include "base/threading/non_thread_safe.h"
 #include "base/time.h"
 #include "base/timer.h"
+#include "content/common/notification_source.h"
 
 namespace base {
 class MessageLoopProxy;
@@ -91,6 +92,8 @@ class ImportantFileWriter : public base::NonThreadSafe {
     commit_interval_ = interval;
   }
 
+  void set_notification_source(NotificationSource source) { source_ = source; }
+
  private:
   // Path being written to.
   const FilePath path_;
@@ -107,6 +110,9 @@ class ImportantFileWriter : public base::NonThreadSafe {
   // Time delta after which scheduled data will be written to disk.
   base::TimeDelta commit_interval_;
 
+  // Used as source for PREF_COMMITTED notification.
+  NotificationSource source_;
+
   DISALLOW_COPY_AND_ASSIGN(ImportantFileWriter);
 };