Address a couple of MSVC warnings.
Address a couple of MSVC warnings.

Change-Id: Ia55f897c09077f977d671d22ae3db4968bc2959b
Reviewed-on: https://code-review.googlesource.com/20970
Reviewed-by: Paul Wankadia <62d4e38bb1380f055ec4b899baa75e52af09c5f7@google.com>

google/re2,google/re2,google/re2,google/re2,google/re2