Avoid gmock warning "Uninteresting mock function call"
Patch by Michael Krebs <mkrebs@chromium.org>, R=me at https://breakpad.appspot.com/397002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1183 4c0a9323-5329-0410-9bdc-e9ce6186880e