Convert GN visibility to be a list.
Convert GN visibility to be a list.

GN visibility currently allows either string or list types, but this is causing
some problems for some templates. I'm going to require it to be lists, so am
changing all callers before pushing the new binary.

R=jam@chromium.org

Review URL: https://codereview.chromium.org/555523002

DrAlexx/pdfium,wwxxyx/pdfium0,azunite/pdf_clone,csharpengineer/pdfium-code,csharpengineer/pdfium-code,chenjian-rits/HelloWorld,andoma/pdfium,azunite/libpdfium,duanhjlt/pdfium,klokantech/pdfium,pwaller/pdfium,nathanstitt/pdfium,csharpengineer/pdfium-code,andoma/pdfium,azunite/pdfium_ch,azunite/pdf_clone,ttyangf/PDFium-,chenjian-rits/HelloWorld,azunite/pdfium_ch,shifucun/pdfium,witwall/pdfium,pwaller/pdfium,chenjian-rits/HelloWorld,andoma/pdfium,DrAlexx/pdfium,duanhjlt/pdfium,witwall/pdfium,wwxxyx/pdfium0,rouault/pdfium,duanhjlt/pdfium,azunite/libpdfium,klokantech/pdfium,was4444/pdfium,bradh/pdfium,shifucun/pdfium,was4444/pdfium,wwxxyx/pdfium0,azunite/pdf_clone,bradh/pdfium,DrAlexx/pdfium,ttyangf/PDFium-,duanhjlt/pdfium,andoma/pdfium,was4444/pdfium,rouault/pdfium,was4444/pdfium,azunite/pdfium_ch,ttyangf/PDFium-,azunite/libpdfium,klokantech/pdfium,rouault/pdfium,DrAlexx/pdfium,shifucun/pdfium,witwall/pdfium,bradh/pdfium,nathanstitt/pdfium,azunite/libpdfium,pwaller/pdfium,nathanstitt/pdfium