Revert 226555 "There is a bug in the mac kernel, which can cause..."

> There is a bug in the mac kernel, which can cause a file descriptor to be closed
> when sent multiple times between processes. By delaying the close on the sender side by
> a few second, we can eliminate this problem.
> 
> BUG=279443, 298276
> 
> Review URL: https://codereview.chromium.org/24365008

This is a speculative revert to fix Mac LayoutTests breakages.
See crbug.com/303487 for detail.

TBR=hubbe@chromium.org

Review URL: https://codereview.chromium.org/25660009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226693 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226693