ozone: Implement zero/one-copy texture for Ozone GBM.

ui/ozone/platform/drm/gpu/gbm_buffer.h

Index: ui/ozone/platform/drm/gpu/gbm_buffer.h
diff --git a/ui/ozone/platform/drm/gpu/gbm_buffer.h b/ui/ozone/platform/drm/gpu/gbm_buffer.h
index 4f420e71df4169554dd6e2a3699a975405089bdf..ef3f0e5976885a97b5c20f87fef2929ee3964dfb 100644
--- a/ui/ozone/platform/drm/gpu/gbm_buffer.h
+++ b/ui/ozone/platform/drm/gpu/gbm_buffer.h
@@ -51,6 +51,9 @@ class GbmPixmap : public NativePixmap {
                             gfx::OverlayTransform plane_transform,
                             const gfx::Rect& display_bounds,
                             const gfx::RectF& crop_rect) override;
+  BufferUsage GetBufferUsage() const override;
+  void* Map() override;
+  void Unmap() override;
 
   scoped_refptr<GbmBuffer> buffer() { return buffer_; }