Mojo: Move platform handle/channel stuff in system to embedder namespace.

These things are exposed through the embedder API (and/or to be used by
the embedder).

R=sky@chromium.org

Review URL: https://codereview.chromium.org/137063010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245303 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245303
envsetup: Stop setting FLOCK.

This was used by the make generator. The ninja generator uses ninja's built-in
"pools" feature for limiting ld parallelism, so this is no longer needed.

BUG=330631
R=torne@chromium.org

Review URL: https://codereview.chromium.org/139263010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245304 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245304