Fix build on non-X11 platforms.

message_loop/message_pump_libevent_unittest.cc

Index: message_loop/message_pump_libevent_unittest.cc
diff --git a/message_loop/message_pump_libevent_unittest.cc b/message_loop/message_pump_libevent_unittest.cc
index 16aba35353d2e63c6652659006b25eb01aa2ca80..d356d6813655783d16e8b5ca6c3061237cab26a3 100644
--- a/message_loop/message_pump_libevent_unittest.cc
+++ b/message_loop/message_pump_libevent_unittest.cc
@@ -290,19 +290,21 @@ class FakeEventSource : public MessagePumpLibevent::EventSource {
   uint32_t work_units_;
 };
 
-TEST_F(MessagePumpLibeventTest, PollEventSource) {
+TEST(MessagePumpLibeventEventSourceTest, Poll) {
+  MessagePumpLibevent* pump = new MessagePumpLibevent;  // owned by |loop|.
+  MessageLoop loop(make_scoped_ptr(pump));
   FakeEventSource event_source;
 
   // Verify event source gets polled repeatedly until no work remains.
-  MessageLoopForUI::current()->SetEventSource(&event_source);
+  pump->SetEventSource(&event_source);
   event_source.set_work_units(5u);
-  ui_loop_->RunUntilIdle();
+  loop.RunUntilIdle();
   EXPECT_EQ(0u, event_source.work_units());
 
   // After removing the event source, it should no longer be polled.
-  MessageLoopForUI::current()->ClearEventSource();
+  pump->ClearEventSource();
   event_source.set_work_units(5u);
-  ui_loop_->RunUntilIdle();
+  loop.RunUntilIdle();
   EXPECT_EQ(5u, event_source.work_units());
 }