diff --git a/mock_service_observer.h b/mock_service_observer.h
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+//
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef UPDATE_ENGINE_MOCK_SERVICE_OBSERVER_H_
+#define UPDATE_ENGINE_MOCK_SERVICE_OBSERVER_H_
+
+#include <gmock/gmock.h>
+#include "update_engine/service_observer_interface.h"
+
+namespace chromeos_update_engine {
+
+class MockServiceObserver : public ServiceObserverInterface {
+ public:
+  MOCK_METHOD5(SendStatusUpdate,
+               void(int64_t last_checked_time,
+                    double progress,
+                    update_engine::UpdateStatus status,
+                    const std::string& new_version,
+                    int64_t new_size));
+  MOCK_METHOD1(SendPayloadApplicationComplete, void(ErrorCode error_code));
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_MOCK_SERVICE_OBSERVER_H_