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 6d8a11249782f0286bfbfb8c7d76bca6155cd8f9..b64ffcebad17fa9cbbe59365b15d7c665f51cb48 100644
--- a/ui/ozone/platform/drm/gpu/gbm_buffer.h
+++ b/ui/ozone/platform/drm/gpu/gbm_buffer.h
@@ -42,6 +42,9 @@ class GbmPixmap : public NativePixmap {
   void* GetEGLClientBuffer() override;
   int GetDmaBufFd() override;
   int GetDmaBufPitch() override;
+  BufferUsage GetBufferUsage() const override;
+  void* Map() override;
+  void Unmap() override;
 
   scoped_refptr<GbmBuffer> buffer() { return buffer_; }