GitLab

This is the windows host focused GN rewrite for Remoting Host. This
work attempts to simplify the build for Remoting so it can be more
easily understood and maintained. This is done by pushing more of the target config checking deeper into the platform specific targets and
producing build files that are more in-line with best-practice GN style.

Review-Url: https://codereview.chromium.org/2308813002
Cr-Commit-Position: refs/heads/master@{#418668}