Fix explain arg
Fix explain arg

Follow up to http://crrev.com/883933002 

TBR=zty@chromium.org

Review URL: https://codereview.chromium.org/884133003

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@293852 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build