Componentize internal class FlagsState in flags_ui component.

components/flags_ui/flags_ui_switches.h

Index: components/flags_ui/flags_ui_switches.h
diff --git a/components/flags_ui/flags_ui_switches.h b/components/flags_ui/flags_ui_switches.h
new file mode 100644
index 0000000000000000000000000000000000000000..a36d28cad9b17143a406de8eb8f281f02b8c79b1
--- /dev/null
+++ b/components/flags_ui/flags_ui_switches.h
@@ -0,0 +1,15 @@
+// Copyright 2015 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 COMPONENTS_FLAGS_UI_FLAGS_UI_SWITCHES_H_
+#define COMPONENTS_FLAGS_UI_FLAGS_UI_SWITCHES_H_
+
+namespace switches {
+
+extern const char kFlagSwitchesBegin[];
+extern const char kFlagSwitchesEnd[];
+
+}  // namespace switches
+
+#endif  // COMPONENTS_FLAGS_UI_FLAGS_UI_SWITCHES_H_