Move font handler and platform-independent shell stuff

GpShell/GpMemoryBuffer.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "HostMemoryBuffer.h"
+
+class GpMemoryBuffer final : public PortabilityLayer::HostMemoryBuffer
+{
+public:
+	void *Contents() override;
+	size_t Size() override;
+	void Destroy() override;
+
+	static GpMemoryBuffer *Create(size_t sz);
+
+private:
+	explicit GpMemoryBuffer(size_t sz);
+	~GpMemoryBuffer();
+
+	static size_t AlignedSize();
+
+	size_t m_size;
+};