Fix clang C++11 compiler warning.
Fix clang C++11 compiler warning.

TBR=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/23658034

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@16617 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh