rasterizer_accelerated: Add intermediary for GPU rasterizers

Add an intermediary class that implements common functions across GPU
accelerated rasterizers. This avoids code repetition on different
backends.

src/video_core/rasterizer_accelerated.h

@@ -0,0 +1,31 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <mutex>
+
+#include <boost/icl/interval_map.hpp>
+
+#include "common/common_types.h"
+#include "video_core/rasterizer_interface.h"
+
+namespace VideoCore {
+
+/// Implements the shared part in GPU accelerated rasterizers in RasterizerInterface.
+class RasterizerAccelerated : public RasterizerInterface {
+public:
+    explicit RasterizerAccelerated();
+    ~RasterizerAccelerated() override;
+
+    void UpdatePagesCachedCount(VAddr addr, u64 size, int delta) override;
+
+private:
+    using CachedPageMap = boost::icl::interval_map<u64, int>;
+    CachedPageMap cached_pages;
+
+    std::mutex pages_mutex;
+};
+
+} // namespace VideoCore