Fix the bug in test analyzer when there is no result in result directory at the beginning.
Fix the bug in test analyzer when there is no result in result directory at the beginning.

BUG=123839
TEST=make sure layout test analyzer runs.

Review URL: https://chromiumcodereview.appspot.com/10108024

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@132600 0039d316-1c4b-4281-b951-d872f2087c98

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