[Extensions] Implement chrome.runtime.openOptionsPage.

chrome/test/data/extensions/api_test/runtime/open_options_page/test.js

+// 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.
+
+// browser_tests --gtest_filter=ExtensionApiTest.OpenOptionsPage
+
+var assertEq = chrome.test.assertEq;
+
+function test() {
+  chrome.test.listenOnce(chrome.runtime.onMessage, function(m, sender) {
+    assertEq('success', m);
+    assertEq(chrome.runtime.id, sender.id);
+    assertEq(chrome.runtime.getURL('options.html'), sender.url);
+  });
+  chrome.runtime.openOptionsPage();
+}
+
+chrome.test.runTests([test]);