Fixes common_unittests build.

Original CL: https://breakpad.appspot.com/5704002/
A=gunsch@chromium.org
R=gunsch@chromium.org

Review URL: https://breakpad.appspot.com/8674002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1378 4c0a9323-5329-0410-9bdc-e9ce6186880e