diff --git a/common/dlcservice_interface.h b/common/dlcservice_interface.h
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+++ b/common/dlcservice_interface.h
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+//
+// Copyright (C) 2018 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_COMMON_DLCSERVICE_INTERFACE_H_
+#define UPDATE_ENGINE_COMMON_DLCSERVICE_INTERFACE_H_
+
+#include <string>
+#include <vector>
+
+#include <base/macros.h>
+
+namespace chromeos_update_engine {
+
+// The abstract dlcservice interface defines the interaction with the
+// platform's dlcservice.
+class DlcServiceInterface {
+ public:
+  virtual ~DlcServiceInterface() = default;
+
+  // Returns true and a list of installed DLC module ids in |dlc_module_ids|.
+  // On failure it returns false.
+  virtual bool GetInstalled(std::vector<std::string>* dlc_module_ids) = 0;
+
+ protected:
+  DlcServiceInterface() = default;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DlcServiceInterface);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_COMMON_DLCSERVICE_INTERFACE_H_