Random: Add seeded PRNG

Source/Core/Common/Random.h

@@ -5,12 +5,37 @@
 #pragma once
 
 #include <cstddef>
+#include <memory>
 #include <type_traits>
 
 #include "Common/CommonTypes.h"
 
 namespace Common::Random
 {
+/// Cryptographically secure pseudo-random number generator, with explicit seed.
+class PRNG final
+{
+public:
+  explicit PRNG(u64 seed) : PRNG(&seed, sizeof(u64)) {}
+  PRNG(void* seed, std::size_t size);
+  ~PRNG();
+
+  void Generate(void* buffer, std::size_t size);
+
+  template <typename T>
+  T GenerateValue()
+  {
+    static_assert(std::is_arithmetic<T>(), "T must be an arithmetic type in GenerateValue.");
+    T value;
+    Generate(&value, sizeof(value));
+    return value;
+  }
+
+private:
+  struct Impl;
+  std::unique_ptr<Impl> m_impl;
+};
+
 /// Fill `buffer` with random bytes using a cryptographically secure pseudo-random number generator.
 void Generate(void* buffer, std::size_t size);