Fix pdfium buildbot build breakage from 336991d.
Fix pdfium buildbot build breakage from 336991d.

Looks like some dependencies were missing during the run at
http://build.chromium.org/p/client.pdfium/builders/linux/builds/31/steps/gyp_pdfium/logs/stdio

TBR=brucedawson@chromium.org
TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/833503003

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