diff --git a/backend/Backend.h b/backend/Backend.h
new file mode 100644
index 0000000..898fece
--- /dev/null
+++ b/backend/Backend.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2020 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 ANDROID_BACKEND_H
+#define ANDROID_BACKEND_H
+
+#include "DrmHwcTwo.h"
+
+namespace android {
+
+class Backend {
+ public:
+  virtual ~Backend() = default;
+  virtual HWC2::Error ValidateDisplay(DrmHwcTwo::HwcDisplay *display,
+                                      uint32_t *num_types,
+                                      uint32_t *num_requests);
+  virtual std::tuple<int, int> GetClientLayers(
+      DrmHwcTwo::HwcDisplay *display,
+      const std::map<uint32_t, DrmHwcTwo::HwcLayer *> &z_map);
+  virtual bool IsClientLayer(DrmHwcTwo::HwcDisplay *display,
+                             DrmHwcTwo::HwcLayer *layer);
+};
+}  // namespace android
+
+#endif