Fix compile of pdf_browsertest.cc after r233162

TBR=pshenoy

Review URL: https://codereview.chromium.org/62493002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233294 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 233294