Xenia: Remove OpenGL

[drillsar]

Since Vulkan is making progress, shouldn't OpenGL be removed completely? Not sure where to start removing this.

[0x8080]

Remove everything under:
xenia-gpu-gl4,
xenia-gpu-gl4-trace-dump,
xenia-gpu-gl4-trace-viewer,
xenia-ui-gl,
etc.

[drillsar]

One file hid_demo.cc not working this is the change. Not sure why it's not working but probably not needed anyway.

original code in this file:

std::unique_ptr<xe::ui::GraphicsProvider> CreateDemoGraphicsProvider(
    xe::ui::Window* window) {
  return xe::ui::gl::GLProvider::Create(window);
}

I changed to:

std::unique_ptr<xe::ui::GraphicsProvider> CreateDemoGraphicsProvider(
    xe::ui::Window* window) {
  return xe::ui::vulkan::VulkanProvider::Create(window);
}

however, I get this error:

hid_demo.obj : error LNK2019: unresolved external symbol "public: static class std::unique_ptr<class xe::ui::GraphicsPr
ovider,struct std::default_delete<class xe::ui::GraphicsProvider> > __cdecl xe::ui::vulkan::VulkanProvider::Create(clas
s xe::ui::Window *)" (?Create@VulkanProvider@vulkan@ui@xe@@SA?AV?$unique_ptr@VGraphicsProvider@ui@xe@@U?$default_delete
@VGraphicsProvider@ui@xe@@@std@@@std@@PEAVWindow@34@@Z) referenced in function "class std::unique_ptr<class xe::ui::Gra
phicsProvider,struct std::default_delete<class xe::ui::GraphicsProvider> > __cdecl xe::hid::CreateDemoGraphicsProvider(
class xe::ui::Window *)" (?CreateDemoGraphicsProvider@hid@xe@@YA?AV?$unique_ptr@VGraphicsProvider@ui@xe@@U?$default_del
ete@VGraphicsProvider@ui@xe@@@std@@@std@@PEAVWindow@ui@2@@Z) [C:\Users\Tom\Documents\xenia\build\xenia-hid-demo.vcxproj
]
bin\Windows\Debug\xenia-hid-demo.exe : fatal error LNK1120: 1 unresolved externals [C:\Users\Tom\Documents\xenia\build\
xenia-hid-demo.vcxproj]

[0x8080]

Just remove
#include "xenia/gpu/gl4/gl4_graphics_system.h"

std::unique_ptr<xe::ui::GraphicsProvider> CreateDemoGraphicsProvider( xe::ui::Window* window) { return xe::ui::gl::GLProvider::Create(window); }

and change
DEFINE_string(gpu, "any", "Graphics system. Use: [any, gl4, vulkan, null]");
to
DEFINE_string(gpu, "any", "Graphics system. Use: [any, vulkan, null]");

[gibbed]

I appreciate the interest here, but you don't need to try and force this issue. @DrChat can do the removal when deemed acceptable.