fixed the second issue in xwalk10 with authentication of CDT socket opened by XDK APX

The first issue was fixed in the class XWalkDevToolsServer a week ago and was enough for xwalk9, but not enough for xwalk10

In addition to the 1st fix there are two more places in this file where content::CanUserConnectToDevTools is registered instead of XWalkDevToolsServer::CanUserConnectToDevTools. For XDK it's enough to fix the registration of callback in the UnixDomainServerSocketFactory class.