MouseCursorMonitor implementation for OSX and Windows.

BUG=crbug.com/173265
R=wez@chromium.org

Review URL: https://webrtc-codereview.appspot.com/2388004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4994 4adac7df-926f-26a2-2b94-8c16560cd09d
12 files changed