Implement D3D12 backend

Source/Core/VideoBackends/D3D12/VideoBackend.h

@@ -0,0 +1,25 @@
+// Copyright 2019 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <string>
+#include "VideoCommon/VideoBackendBase.h"
+
+namespace DX12
+{
+class VideoBackend final : public VideoBackendBase
+{
+public:
+  bool Initialize(const WindowSystemInfo& wsi) override;
+  void Shutdown() override;
+
+  std::string GetName() const override;
+  std::string GetDisplayName() const override;
+  void InitBackendInfo() override;
+
+private:
+  void FillBackendInfo();
+};
+}