GitLab

The WindowTreeHost and ContextFactory implementations are specific to
the view manager and should be moved there. No one else should be
using these directly. I'm also nuking launcher as it was temporary and
the only other place that was using this code.

BUG=365012
TEST=none
R=ben@chromium.org

Review URL: https://codereview.chromium.org/315223004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275453 0039d316-1c4b-4281-b951-d872f2087c98