Remove the 'callback_ms' function from EventLoop

This is a peculiar function to require event loops to implement, and it's only
used in one spot during tests right now. Instead, a possibly more robust apis
for timers should be used rather than requiring all event loops to implement a
curious-looking function.

src/libstd/rt/rtio.rs

@@ -28,7 +28,6 @@ pub trait EventLoop {
     fn run(&mut self);
     fn callback(&mut self, ~fn());
     fn pausible_idle_callback(&mut self) -> ~PausibleIdleCallback;
-    fn callback_ms(&mut self, ms: u64, ~fn());
     fn remote_callback(&mut self, ~fn()) -> ~RemoteCallback;
 
     /// The asynchronous I/O services. Not all event loops may provide one

src/libstd/rt/sched.rs

@@ -1147,22 +1147,15 @@ mod test {
 
     #[test]
     fn test_io_callback() {
+        use rt::io::timer;
+
         // This is a regression test that when there are no schedulable tasks
         // in the work queue, but we are performing I/O, that once we do put
         // something in the work queue again the scheduler picks it up and doesn't
         // exit before emptying the work queue
         do run_in_newsched_task {
             do spawntask {
-                let sched: ~Scheduler = Local::take();
-                do sched.deschedule_running_task_and_then |sched, task| {
-                    let task = Cell::new(task);
-                    do sched.event_loop.callback_ms(10) {
-                        rtdebug!("in callback");
-                        let mut sched: ~Scheduler = Local::take();
-                        sched.enqueue_blocked_task(task.take());
-                        Local::put(sched);
-                    }
-                }
+                timer::sleep(10);
             }
         }
     }

src/libstd/rt/uv/uvio.rs

@@ -222,15 +222,6 @@ impl EventLoop for UvEventLoop {
         } as ~PausibleIdleCallback
     }
 
-    fn callback_ms(&mut self, ms: u64, f: ~fn()) {
-        let mut timer =  TimerWatcher::new(self.uvio.uv_loop());
-        do timer.start(ms, 0) |timer, status| {
-            assert!(status.is_none());
-            timer.close(||());
-            f();
-        }
-    }
-
     fn remote_callback(&mut self, f: ~fn()) -> ~RemoteCallback {
         ~UvRemoteCallback::new(self.uvio.uv_loop(), f) as ~RemoteCallback
     }