Replace base::get with std::get

base::get is no longer needed after the linux sysroot update. The new
sysroot has libstdc++-4.8, that has rvalue reference support of
std::tuple.

Review-Url: https://codereview.chromium.org/2797133002
Cr-Commit-Position: refs/heads/master@{#462229}
4 files changed