Implement an initial extension settings API.

chrome/browser/extensions/extension_settings_apitest.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 "base/command_line.h"
+#include "chrome/browser/extensions/extension_apitest.h"
+#include "chrome/common/chrome_switches.h"
+#include "net/base/mock_host_resolver.h"
+
+class ExtensionSettingsApiTest : public ExtensionApiTest {
+};
+
+IN_PROC_BROWSER_TEST_F(ExtensionSettingsApiTest, Settings) {
+  CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kEnableExperimentalExtensionApis);
+  ASSERT_TRUE(RunExtensionTest("settings")) << message_;
+}