[cros] Add --stub-cros-settings option for testing.

chrome/browser/chromeos/cros_settings_provider.cc

 // 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.
 
 #include "chrome/browser/chromeos/cros_settings_provider.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "base/values.h"
 #include "chrome/common/chrome_switches.h"
 
 namespace chromeos {
 
+CrosSettingsProvider::CrosSettingsProvider(
+    const NotifyObserversCallback& notify_cb)
+  : notify_cb_(notify_cb) {
+}
+
+CrosSettingsProvider::~CrosSettingsProvider() {
+}
+
 void CrosSettingsProvider::Set(const std::string& path,
                                const base::Value& value) {
   // We don't allow changing any of the cros settings without prefix
   // "cros.session." in the guest mode.
   // It should not reach here from UI in the guest mode, but just in case.
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kGuestSession) &&
       !::StartsWithASCII(path, "cros.session.", true)) {
     LOG(ERROR) << "Ignoring the guest request to change: " << path;
     return;
   }
   DoSet(path, value);
 }
 
+void CrosSettingsProvider::NotifyObservers(const std::string& path) {
+  notify_cb_.Run(path);
+}
+
 };  // namespace chromeos