Simplifying GPU creation.

Part of #296.

src/xenia/gpu/gl4/gl4_gpu.cc

@@ -7,10 +7,7 @@
  ******************************************************************************
  */
 
-#include "xenia/gpu/gl4/gl4_gpu.h"
-
 #include "xenia/gpu/gl4/gl4_gpu-private.h"
-#include "xenia/gpu/gl4/gl4_graphics_system.h"
 
 DEFINE_bool(thread_safe_gl, false,
             "Only allow one GL context to be active at a time.");
@@ -30,33 +27,3 @@ DEFINE_bool(vendor_gl_extensions, false,
 DEFINE_bool(disable_framebuffer_readback, false,
             "Disable framebuffer readback.");
 DEFINE_bool(disable_textures, false, "Disable textures and use colors only.");
-
-namespace xe {
-namespace gpu {
-namespace gl4 {
-
-void InitializeIfNeeded();
-void CleanupOnShutdown();
-
-void InitializeIfNeeded() {
-  static bool has_initialized = false;
-  if (has_initialized) {
-    return;
-  }
-  has_initialized = true;
-
-  //
-
-  atexit(CleanupOnShutdown);
-}
-
-void CleanupOnShutdown() {}
-
-std::unique_ptr<GraphicsSystem> Create(Emulator* emulator) {
-  InitializeIfNeeded();
-  return std::make_unique<GL4GraphicsSystem>(emulator);
-}
-
-}  // namespace gl4
-}  // namespace gpu
-}  // namespace xe