Chromecast fix: MetricsStateManager segfaults if callbacks are empty.

chromecast/metrics/cast_metrics_service_client_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 "chromecast/metrics/cast_metrics_service_client.h"
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/prefs/testing_pref_service.h"
+#include "components/metrics/metrics_service.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace chromecast {
+
+class CastMetricsTest : public testing::Test {
+ public:
+  CastMetricsTest() {}
+  virtual ~CastMetricsTest() {}
+
+ protected:
+  virtual void SetUp() OVERRIDE {
+    message_loop_.reset(new base::MessageLoop());
+    prefs_.reset(new TestingPrefServiceSimple());
+    ::metrics::MetricsService::RegisterPrefs(prefs_->registry());
+  }
+
+  TestingPrefServiceSimple* prefs() { return prefs_.get(); }
+
+ private:
+  scoped_ptr<base::MessageLoop> message_loop_;
+  scoped_ptr<TestingPrefServiceSimple> prefs_;
+
+  DISALLOW_COPY_AND_ASSIGN(CastMetricsTest);
+};
+
+TEST_F(CastMetricsTest, CreateMetricsServiceClient) {
+  // Create and expect this to not crash.
+  metrics::CastMetricsServiceClient::Create(prefs(), NULL);
+}
+
+}  // namespace chromecast