Adding the multi profile feature to allow drag of windows from the active desktop to another ones desktop.

How it works:
When multiple users are loaded, the current user can drag one of the windows on his desktop to a user's icon on the tray menu. If a transfer to that icon is possible, the window will "zap back" to it's original location to indicate the operation. If he drops the window there it will be transferred to the other users desktop.

BUG=305068
TEST=visual

Review URL: https://codereview.chromium.org/27042003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228523 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228523