remoting: Use stl utilities from the base namespace

The utilities in base/stl_util.h have been moved from the global
into the base namespace. This patch updates the call sites accordingly.

No functional changes.

BUG=636301

Review-Url: https://codereview.chromium.org/2230193002
Cr-Commit-Position: refs/heads/master@{#411604}
18 files changed