Restructure RawChannelPosix and RawChannel, so that the platform-independent logic can be shared between POSIX and Windows.

BUG=None
TEST=mojo_system_unittests
[email protected]

Review URL: https://codereview.chromium.org/169723004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253865 0039d316-1c4b-4281-b951-d872f2087c98
4 files changed