[D3D12] Refactor root signature creation

src/xenia/ui/d3d12/d3d12_util.h

@@ -0,0 +1,37 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2018 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_UI_D3D12_D3D12_UTIL_H_
+#define XENIA_UI_D3D12_D3D12_UTIL_H_
+
+#include "xenia/ui/d3d12/d3d12_provider.h"
+
+namespace xe {
+namespace ui {
+namespace d3d12 {
+namespace util {
+
+inline bool ReleaseAndNull(IUnknown*& object) {
+  if (object != nullptr) {
+    object->Release();
+    object = nullptr;
+    return true;
+  }
+  return false;
+};
+
+ID3D12RootSignature* CreateRootSignature(ID3D12Device* device,
+                                         const D3D12_ROOT_SIGNATURE_DESC& desc);
+
+}  // namespace util
+}  // namespace d3d12
+}  // namespace ui
+}  // namespace xe
+
+#endif  // XENIA_UI_D3D12_D3D12_UTIL_H_