By the way 'out/debug/pdfium_test --png /home/a/mozilla.pdf' runs ok and produce images.
So i must find the pdfium_test code to see how it works.
But i am emotionally connect with wxWidgets framework for all this job have done, so i'd like to use wxPDFView in my project.
BTW *buildtools is the folder that gn.py uses for making args.gn file (gn args out/debug) in out/debug dir.
If we clone from github there is not this folder. So we must use instructions as above exactly and download from google-git. I write those things to remember and for anyone that will help.