Revert of Move base/prefs to components/prefs

base/prefs/scoped_user_pref_update.cc

Index: base/prefs/scoped_user_pref_update.cc
diff --git a/base/prefs/scoped_user_pref_update.cc b/base/prefs/scoped_user_pref_update.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1440a5711d8f911d545dbcbbc792abb464bb13de
--- /dev/null
+++ b/base/prefs/scoped_user_pref_update.cc
@@ -0,0 +1,37 @@
+// Copyright 2013 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.
+
+#include "base/prefs/scoped_user_pref_update.h"
+
+#include "base/logging.h"
+#include "base/prefs/pref_notifier.h"
+#include "base/prefs/pref_service.h"
+
+namespace subtle {
+
+ScopedUserPrefUpdateBase::ScopedUserPrefUpdateBase(PrefService* service,
+                                                   const std::string& path)
+    : service_(service), path_(path), value_(NULL) {
+  DCHECK(service_->CalledOnValidThread());
+}
+
+ScopedUserPrefUpdateBase::~ScopedUserPrefUpdateBase() {
+  Notify();
+}
+
+base::Value* ScopedUserPrefUpdateBase::GetValueOfType(base::Value::Type type) {
+  DCHECK(CalledOnValidThread());
+  if (!value_)
+    value_ = service_->GetMutableUserPref(path_, type);
+  return value_;
+}
+
+void ScopedUserPrefUpdateBase::Notify() {
+  if (value_) {
+    service_->ReportUserPrefChanged(path_);
+    value_ = NULL;
+  }
+}
+
+}  // namespace subtle