Refactor shader GPU state and memory access (#1203)

* Refactor shader GPU state and memory access

* Fix NVDEC project build

* Address PR feedback and add missing XML comments

Ryujinx.Graphics.Gpu/Shader/ShaderCodeHolder.cs

@@ -0,0 +1,44 @@
+using Ryujinx.Graphics.GAL;
+using Ryujinx.Graphics.Shader;
+
+namespace Ryujinx.Graphics.Gpu.Shader
+{
+    /// <summary>
+    /// Cached shader code for a single shader stage.
+    /// </summary>
+    class ShaderCodeHolder
+    {
+        /// <summary>
+        /// Shader program containing translated code.
+        /// </summary>
+        public ShaderProgram Program { get; }
+
+        /// <summary>
+        /// Host shader object.
+        /// </summary>
+        public IShader HostShader { get; set; }
+
+        /// <summary>
+        /// Maxwell binary shader code.
+        /// </summary>
+        public byte[] Code { get; }
+
+        /// <summary>
+        /// Optional maxwell binary shader code for "Vertex A" shader.
+        /// </summary>
+        public byte[] Code2 { get; }
+
+        /// <summary>
+        /// Creates a new instace of the shader code holder.
+        /// </summary>
+        /// <param name="program">Shader program</param>
+        /// <param name="code">Maxwell binary shader code</param>
+        /// <param name="code2">Optional binary shader code of the "Vertex A" shader, when combined with "Vertex B"</param>
+        public ShaderCodeHolder(ShaderProgram program, byte[] code, byte[] code2 = null)
+        {
+            Program = program;
+            Code    = code;
+            Code2   = code2;
+        }
+    }
+}