Core: Add ability to specify and launch a riivolution-modded game via a .json file.

Source/Core/DiscIO/GameModDescriptor.h

@@ -0,0 +1,46 @@
+// Copyright 2021 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <optional>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "Common/CommonTypes.h"
+
+namespace DiscIO
+{
+struct GameModDescriptorRiivolutionPatchOption
+{
+  std::string section_name;
+  std::string option_id;
+  std::string option_name;
+  u32 choice = 0;
+};
+
+struct GameModDescriptorRiivolutionPatch
+{
+  std::string xml;
+  std::string root;
+  std::vector<GameModDescriptorRiivolutionPatchOption> options;
+};
+
+struct GameModDescriptorRiivolution
+{
+  std::vector<GameModDescriptorRiivolutionPatch> patches;
+};
+
+struct GameModDescriptor
+{
+  std::string base_file;
+  std::string display_name;
+  std::string banner;
+  std::optional<GameModDescriptorRiivolution> riivolution = std::nullopt;
+};
+
+std::optional<GameModDescriptor> ParseGameModDescriptorFile(const std::string& filename);
+std::optional<GameModDescriptor> ParseGameModDescriptorString(std::string_view json,
+                                                              std::string_view json_path);
+}  // namespace DiscIO