release 2019-04-01
Get rid of `using std::string;`. (part 7 of 7)

Change-Id: I2df2ec398bb0a5d9ac9019f575c494107a82fbe3
Reviewed-on: https://code-review.googlesource.com/c/re2/+/39136
Reviewed-by: Paul Wankadia <junyer@google.com>
3 files changed