Use of base::StringPairs appropriately in server

Bescause base/strings/string_split.h defines:
typedef std::vector<std::pair<std::string, std::string> > StringPairs;

BUG=412250

Review URL: https://codereview.chromium.org/1093823005

Cr-Commit-Position: refs/heads/master@{#327241}
1 file changed