LibWeb/WebGL: Request GL_ANGLE_instanced_arrays extension when required

Author: https://github.com/Lubrsi
Commit: 58942e1137
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3239
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/kalenikaliaksandr

Libraries/LibWeb/WebGL/OpenGLContext.h

@@ -34,6 +34,7 @@ public:
     u32 default_renderbuffer() const;
 
     Vector<String> get_supported_extensions();
+    void request_extension(char const* extension_name);
 
 private:
     NonnullRefPtr<Gfx::SkiaBackendContext> m_skia_backend_context;