Convert Ozone GL OSMesa implementation.

ui/ozone/platform/headless/headless_surface_factory.h

Index: ui/ozone/platform/headless/headless_surface_factory.h
diff --git a/ui/ozone/platform/headless/headless_surface_factory.h b/ui/ozone/platform/headless/headless_surface_factory.h
index dfe3d3ecb05cb61da86b2ca0e186c85813596d26..f2748826ced67e31bab05d40a6c7aa632a591ef4 100644
--- a/ui/ozone/platform/headless/headless_surface_factory.h
+++ b/ui/ozone/platform/headless/headless_surface_factory.h
@@ -5,7 +5,11 @@
 #ifndef UI_OZONE_PLATFORM_HEADLESS_HEADLESS_SURFACE_FACTORY_H_
 #define UI_OZONE_PLATFORM_HEADLESS_HEADLESS_SURFACE_FACTORY_H_
 
+#include <memory>
+#include <vector>
+
 #include "base/macros.h"
+#include "ui/ozone/public/gl_ozone.h"
 #include "ui/ozone/public/surface_factory_ozone.h"
 
 namespace ui {
@@ -19,6 +23,8 @@ class HeadlessSurfaceFactory : public SurfaceFactoryOzone {
   ~HeadlessSurfaceFactory() override;
 
   // SurfaceFactoryOzone:
+  std::vector<gl::GLImplementation> GetAllowedGLImplementations() override;
+  GLOzone* GetGLOzone(gl::GLImplementation implementation) override;
   std::unique_ptr<SurfaceOzoneCanvas> CreateCanvasForWidget(
       gfx::AcceleratedWidget w) override;
   scoped_refptr<NativePixmap> CreateNativePixmap(
@@ -30,6 +36,8 @@ class HeadlessSurfaceFactory : public SurfaceFactoryOzone {
  private:
   HeadlessWindowManager* window_manager_;
 
+  std::unique_ptr<GLOzone> osmesa_implementation_;
+
   DISALLOW_COPY_AND_ASSIGN(HeadlessSurfaceFactory);
 };