Extension Settings API: move the API functions into an object SettingsNamepace,

chrome/browser/extensions/settings/settings_namespace.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/extensions/settings/settings_namespace.h"
+
+#include "base/logging.h"
+
+namespace extensions {
+
+namespace settings_namespace {
+
+namespace {
+const char* kLocalNamespace = "local";
+const char* kSyncNamespace  = "sync";
+}  // namespace
+
+std::string ToString(Namespace settings_namespace) {
+  switch (settings_namespace) {
+    case LOCAL: return kLocalNamespace;
+    case SYNC:  return kSyncNamespace;
+    case INVALID:
+    default: NOTREACHED();
+  }
+  return std::string();
+}
+
+Namespace FromString(const std::string& namespace_string) {
+  if (namespace_string == kLocalNamespace)
+    return LOCAL;
+  else if (namespace_string == kSyncNamespace)
+    return SYNC;
+  return INVALID;
+}
+
+}  // namespace settings_namespace
+
+}  // namespace extensions