nullvideo: initial release of null video backend

Source/Core/VideoBackends/Null/VideoBackend.h

@@ -0,0 +1,25 @@
+// Copyright 2015 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "VideoCommon/VideoBackendBase.h"
+
+namespace Null
+{
+class VideoBackend : public VideoBackendBase
+{
+  bool Initialize(void* window_handle) override;
+  void Shutdown() override;
+
+  std::string GetName() const override { return "Null"; }
+  std::string GetDisplayName() const override { return "Null"; }
+  void Video_Prepare() override;
+  void Video_Cleanup() override;
+
+  void ShowConfig(void* parent) override;
+
+  unsigned int PeekMessages() override { return 0; }
+};
+}