Use std::move() instead of scoped_ptr<>::Pass() in remoting/protocol

Now there is a presubmit check that doesn't allow Pass() anymore.
See https://www.chromium.org/rvalue-references for information
about std::move in chromium.

Review URL: https://codereview.chromium.org/1534193004

Cr-Commit-Position: refs/heads/master@{#366687}
55 files changed