Remove base::internal::PassingTraits

PassingTraits is a injection point to control base::Callback behavior
around an internal value transfer. However as it doesn't have a user
outside of the file, and is probably not worth exposing.

This CL replaces the injection point with single std::conditional for
simpler code.

Change-Id: I0cc10ad148fbd9f041eb9a5a3097c5a8ef77b473
Reviewed-on: https://chromium-review.googlesource.com/1118061
Commit-Queue: Daniel Cheng <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/master@{#571240}
3 files changed