Core: Add loading screen based progress callbacks

src/core/host_interface_progress_callback.h

@@ -0,0 +1,32 @@
+#pragma once
+#include "common/progress_callback.h"
+#include "host_interface.h"
+
+class HostInterfaceProgressCallback : public BaseProgressCallback
+{
+public:
+  HostInterfaceProgressCallback(HostInterface* intf);
+
+  void PushState() override;
+  void PopState() override;
+
+  void SetCancellable(bool cancellable) override;
+  void SetStatusText(const char* text) override;
+  void SetProgressRange(u32 range) override;
+  void SetProgressValue(u32 value) override;
+
+  void DisplayError(const char* message) override;
+  void DisplayWarning(const char* message) override;
+  void DisplayInformation(const char* message) override;
+  void DisplayDebugMessage(const char* message) override;
+
+  void ModalError(const char* message) override;
+  bool ModalConfirmation(const char* message) override;
+  u32 ModalPrompt(const char* message, u32 num_options, ...) override;
+  
+private:
+  void Redraw(bool force);
+
+  HostInterface* m_host_interface;
+  int m_last_progress_percent = -1;
+};