Fix some clang warnings with -Wmissing-braces in printing.

Fix some clang warnings with -Wmissing-braces in printing.

Clang warns if there are missing braces around a subobject
initializer. The most common idiom that triggers this is:
  STRUCT s = {0};
if the first field of STRUCT is itself a struct. This can
be more simply written as:
  STRUCT s = {};
which also prevents the warning from firing.

BUG=505297
Committed: https://crrev.com/475b2e8fdde79348aaef7ffab71a283f4171a733
Cr-Commit-Position: refs/heads/master@{#337086}

[dcheng, 2015-07-01 18:32:23]

dcheng@chromium.org changed reviewers:
+ vitalybuka@chromium.org

[Vitaly Buka (NO REVIEWS), 2015-07-01 18:41:08]

The CQ bit was checked by vitalybuka@chromium.org

[Vitaly Buka (NO REVIEWS), 2015-07-01 18:41:08]

lgtm

[commit-bot: I haz the power, 2015-07-01 18:42:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1221643016/1

[commit-bot: I haz the power, 2015-07-01 19:17:08]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-01 19:18:04]

Patchset 1 (id:??) landed as
https://crrev.com/475b2e8fdde79348aaef7ffab71a283f4171a733
Cr-Commit-Position: refs/heads/master@{#337086}