Fix Visual Studio warning on single file compilation

BUG=615402

Review-Url: https://codereview.chromium.org/2018733003
Cr-Original-Commit-Position: refs/heads/master@{#396693}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: a7e95b0468908825cdafa072ed1b8f99f3859a93
1 file changed
tree: b731fdae2e44053c793b677a06fc915d939769c4
  1. tools/