Add more Rappor metrics

chrome/browser/metrics/rappor/sampling_unittest.cc

+// Copyright 2014 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/metrics/rappor/sampling.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "url/gurl.h"
+
+namespace rappor {
+
+// Make sure recording a sample during tests, when the Rappor service is NULL,
+// doesn't cause a crash.
+TEST(RapporSamplingTest, SmokeTest) {
+  SampleDomainAndRegistryFromHost(std::string(), std::string());
+  SampleDomainAndRegistryFromGURL(std::string(), GURL());
+}
+
+}  // namespace rappor