Remove calls to MessageLoop::current() in net.

net/dns/serial_worker_unittest.cc

Index: net/dns/serial_worker_unittest.cc
diff --git a/net/dns/serial_worker_unittest.cc b/net/dns/serial_worker_unittest.cc
index 89fdb211bcfbdeb4b430213bf9b305329866f5ce..f85ff53b9b9beab236281febb50fe108a06685e2 100644
--- a/net/dns/serial_worker_unittest.cc
+++ b/net/dns/serial_worker_unittest.cc
@@ -57,7 +57,7 @@ class SerialWorkerTest : public testing::Test {
   }
 
   void OnWorkFinished() {
-    EXPECT_TRUE(message_loop_ == base::MessageLoop::current());
+    EXPECT_TRUE(message_loop_->task_runner()->BelongsToCurrentThread());
     EXPECT_EQ(output_value_, input_value_);
     BreakNow("OnWorkFinished");
   }