Remove callbacks for SurfaceFactoryOzone::LoadEGLGLES2Bindings().

ui/ozone/platform/headless/headless_surface_factory.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_OZONE_PLATFORM_HEADLESS_HEADLESS_SURFACE_FACTORY_H_
 #define UI_OZONE_PLATFORM_HEADLESS_HEADLESS_SURFACE_FACTORY_H_
 
 #include "base/macros.h"
 #include "ui/ozone/public/surface_factory_ozone.h"
 
 namespace ui {
 
 class HeadlessWindowManager;
 
 class HeadlessSurfaceFactory : public SurfaceFactoryOzone {
  public:
   HeadlessSurfaceFactory();
   explicit HeadlessSurfaceFactory(HeadlessWindowManager* window_manager);
   ~HeadlessSurfaceFactory() override;
 
   // SurfaceFactoryOzone:
   std::unique_ptr<SurfaceOzoneCanvas> CreateCanvasForWidget(
       gfx::AcceleratedWidget w) override;
-  bool LoadEGLGLES2Bindings(
-      AddGLLibraryCallback add_gl_library,
-      SetGLGetProcAddressProcCallback set_gl_get_proc_address) override;
   scoped_refptr<NativePixmap> CreateNativePixmap(
       gfx::AcceleratedWidget widget,
       gfx::Size size,
       gfx::BufferFormat format,
       gfx::BufferUsage usage) override;
 
  private:
   HeadlessWindowManager* window_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(HeadlessSurfaceFactory);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_HEADLESS_HEADLESS_SURFACE_FACTORY_H_