Fix DCHECK error on mac buildbot. Review URL: https://chromiumcodereview.appspot.com/9423005
Fix DCHECK error on mac buildbot.
Review URL: https://chromiumcodereview.appspot.com/9423005

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@122530 0039d316-1c4b-4281-b951-d872f2087c98

ropik/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,ropik/chromium,gavinp/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,yitian134/chromium,gavinp/chromium,ropik/chromium,yitian134/chromium,ropik/chromium,ropik/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,ropik/chromium