video_core: Abstract vk_sampler_cache into a templated class

src/video_core/sampler_cache.cpp

@@ -0,0 +1,21 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/cityhash.h"
+#include "common/common_types.h"
+#include "video_core/sampler_cache.h"
+
+namespace VideoCommon {
+
+std::size_t SamplerCacheKey::Hash() const {
+    static_assert(sizeof(raw) % sizeof(u64) == 0);
+    return static_cast<std::size_t>(
+        Common::CityHash64(reinterpret_cast<const char*>(raw.data()), sizeof(raw) / sizeof(u64)));
+}
+
+bool SamplerCacheKey::operator==(const SamplerCacheKey& rhs) const {
+    return raw == rhs.raw;
+}
+
+} // namespace VideoCommon