Add ManagedUserSettingsService and a SupervisedUserPrefStore using it.

chrome/browser/managed_mode/managed_user_constants.h

Index: chrome/browser/managed_mode/managed_user_constants.h
diff --git a/chrome/browser/managed_mode/managed_user_constants.h b/chrome/browser/managed_mode/managed_user_constants.h
new file mode 100644
index 0000000000000000000000000000000000000000..356fbe0115baf43f4a4ca2bed5b6fab2e80fccd8
--- /dev/null
+++ b/chrome/browser/managed_mode/managed_user_constants.h
@@ -0,0 +1,17 @@
+// 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.
+
+#ifndef CHROME_BROWSER_MANAGED_MODE_MANAGED_USER_CONSTANTS_H_
+#define CHROME_BROWSER_MANAGED_MODE_MANAGED_USER_CONSTANTS_H_
+
+namespace managed_users {
+
+extern const char kContentPackDefaultFilteringBehavior[];
+extern const char kContentPackManualBehaviorHosts[];
+extern const char kContentPackManualBehaviorURLs[];
+extern const char kForceSafeSearch[];
+
+}  // managed_users
+
+#endif  // CHROME_BROWSER_MANAGED_MODE_MANAGED_USER_CONSTANTS_H_