clang/win: Fix a -Wmissing-braces regression from https://codereview.chromium.org/1563183008/
clang/win: Fix a -Wmissing-braces regression from https://codereview.chromium.org/1563183008/

No behavior change.

BUG=547914,82385
TBR=bsep@chromium.org

Review URL: https://codereview.chromium.org/1589253002 .

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#369661}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk